Cloud Condensation
Nuclei (CCN) Counter
Manual
for Single-Column CCNs
DOC-0086 Revision I-2
2545 Central Avenue
Boulder, CO 80301-5727 USA
COPYRIGHT © 2012 DROPLET MEASUREMENT TECHNOLOGIES,
INC.
Manual, Cloud Condensation Nuclei Counter
DOC-0086 Rev I-2
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Manual, Cloud Condensation Nuclei Counter
Copyright © 2012 Droplet Measurement Technologies, Inc.
2545 CENTRAL AVENUE
BOULDER, COLORADO, USA 80301-5727
TEL: +1 (303) 440-5576
FAX: +1 (303) 440-1965
WWW.DROPLETMEASUREMENT.COM
All rights reserved. No part of this document shall be reproduced, stored in a retrieval system, or
transmitted by any means, electronic, mechanical, photocopying, recording, or otherwise, without
written permission from Droplet Measurement Technologies, Inc. Although every precaution has
been taken in the preparation of this document, Droplet Measurement Technologies, Inc. assumes
no responsibility for errors or omissions. Neither is any liability assumed for damages resulting from
the use of the information contained herein.
Information in this document is subject to change without prior notice in order to improve accuracy,
design, and function and does not represent a commitment on the part of the manufacturer.
Information furnished in this manual is believed to be accurate and reliable. However, no
responsibility is assumed for its use, or any infringements of patents or other rights of third parties,
which may result from its use.
Trademark Information
All Droplet Measurement Technologies, Inc. product names and the Droplet Measurement
Technologies, Inc. logo are trademarks of Droplet Measurement Technologies, Inc.
All other brands and product names are trademarks or registered trademarks of their respective
owners.
Warranty
The seller warrants that the equipment supplied will be free from defects in material and
workmanship for a period of one year from the confirmed date of purchase of the original buyer.
Service procedures and repairs are warrantied for 90 days. The equipment owner will pay for
shipping to DMT, while DMT covers the return shipping expense.
Consumable components, such as tubing, filters, pump diaphragms, and Nafion humidifiers and
dehumidifiers are not covered by this warranty.
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Manual, Cloud Condensation Nuclei Counter
Software Licensing Agreement
DMT licenses CCN software only upon the condition that you accept all of the terms contained in this
license agreement.
This software is provided by DMT “as is” and any express or implied warranties, including, but not
limited to, the implied warranties of merchantability and fitness for a particular purpose are
disclaimed. Under no circumstances and under no legal theory, whether in tort, contract, or
otherwise, shall DMT or its developers be liable for any direct, indirect, incidental, special,
exemplary, or consequential damages (including damages for work stoppage; computer failure or
malfunction; loss of goodwill; loss of use, data or profits; or for any and all other damages and
losses).
Some states do not allow the limitation or exclusion of implied warranties and you may be entitled to
additional rights in those states.
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CONTENTS
PART I: THE CCN INSTRUMENT ........................................................... 10
1.0
1.1
1.2
1.3
1.4
1.5
2.0
Product Description ............................................................... 10
Introduction ................................................................................ 10
CCN Specifications and Features ........................................................ 11
Electrical Specifications .................................................................. 12
Physical Specifications .................................................................... 12
Operating Limits ........................................................................... 13
Theory of Operation .............................................................. 13
2.1
How the CCN Generates Supersaturation .............................................. 13
2.2
Details of CCN Design ..................................................................... 14
2.2.1 Flow of Air and Water through the CCN ........................................... 15
2.2.2 CCN Components ...................................................................... 18
3.0
Setting up the CCN ................................................................ 20
3.1
Unpacking the CCN ........................................................................ 21
3.1.1 Removing Instrument from Shipping Case ......................................... 21
3.1.2 Connecting Instrument Components................................................ 22
3.1.3 USB Memory Stick ..................................................................... 24
3.2
Setting Flow and Humidifying CCN ...................................................... 24
3.3
Checking that the CCN is Functioning Properly ....................................... 26
3.3.1 Testing the Unit for Leaks (for CCN Use on Pressurized Aircraft) ............. 27
3.4
Repacking the CCN for Shipping ......................................................... 28
3.5
Drying the CCN Prior to Shipping ........................................................ 29
3.5.1 Necessity of Drying CCN .............................................................. 29
3.5.2 To Drain All Liquid Water ............................................................ 29
4.0
4.1
Installation .......................................................................... 30
Power Supply Considerations ............................................................ 30
5.0
CCN Power and Signal Connections ............................................ 31
6.0
Printed Circuit Boards (PCBs) ................................................... 33
7.0
CCN Maintenance .................................................................. 35
7.1
7.2
7.3
7.4
7.5
Every 4 days and Before Every Flight ................................................... 35
Every Month ................................................................................ 36
Every Three Months ....................................................................... 37
Every Year .................................................................................. 37
Pump Diaphragm and Motor Maintenance Requirements ............................ 38
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8.0
Calibration Procedures ........................................................... 38
8.1
CCN SS% Calibration ....................................................................... 38
8.1.1 Recommended calibration equipment ............................................. 38
8.1.2 SS% Calibration Procedure ........................................................... 39
8.2
Flow Calibrations .......................................................................... 40
8.2.1 Recommended Calibration Equipment ............................................. 40
8.2.2 Flow Calibrations Procedure......................................................... 40
8.3
Pressure Calibration ....................................................................... 44
8.3.1 Recommended calibration equipment ............................................. 44
8.3.2 Pressure Calibration Procedure ..................................................... 44
8.4
OPC Calibration ............................................................................ 45
8.4.1 Recommended Calibration Equipment ............................................. 45
8.4.2 OPC Calibration Procedure .......................................................... 45
8.4.3 OPC Cleaning Procedure.............................................................. 46
9.0
CCN Accessories .................................................................... 48
9.1
9.2
Spares and Consumable Supplies ........................................................ 48
Airborne CCN Inlet Assembly Kit ........................................................ 50
10.0
Troubleshooting .................................................................... 50
PART II: THE CCN SOFTWARE ............................................................. 59
11.0
11.1
12.0
Product Description ............................................................... 59
Introduction ................................................................................ 59
SINGLE CCN.exe (Main Program) ............................................... 60
12.1 Control Tabs ................................................................................ 61
12.1.1
SS Tab (Supersaturation Settings) ................................................ 61
12.1.1.1 SS Tab Settings that Must be Configured in First 10 Seconds .......... 61
12.1.1.2 SS Tab General Settings ..................................................... 62
12.1.2
Temps Tab (Temperatures) ....................................................... 64
12.1.2.1 CCN Temperature Adjustment .............................................. 66
12.1.3
Flows Tab ............................................................................ 67
12.1.4
OPC Tab (Optical Particle Counter) .............................................. 70
12.1.5
Monitor Tab (Alarm Monitoring).................................................. 72
12.1.5.1 CCN Alerts and Alarms ....................................................... 73
12.1.5.2 How to Interpret CCN Alarm Codes in Output Files ..................... 74
12.1.6
Chart Tab ............................................................................ 75
12.1.7
Prog Tab (Program Control) ....................................................... 76
12.2 Histogram ................................................................................... 77
12.3 Particle Concentration Time-Series Chart ............................................. 78
12.4 Other Time-Series Charts and DMT Service Tab ....................................... 78
12.4.1
Serial Output Tab ................................................................... 78
12.4.2
DMT Service Tab .................................................................... 80
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12.4.2.1 DMT Service Tab: PID Section ............................................... 81
12.4.2.2 DMT Service Tab: Gains Section ............................................ 82
12.4.2.3 DMT Service Tab: FlowCal Section ......................................... 82
12.4.2.4 DMT Service Tab Error / Exit ............................................... 83
12.5 Program Input Files........................................................................ 84
12.6 Program Output Data ..................................................................... 85
12.6.1
Serial Stream ........................................................................ 85
12.6.2
Output Files ......................................................................... 86
13.0
CCN SS Settings Config Editor.exe ............................................. 87
14.0
CCN Calibration Editor.exe ...................................................... 89
14.1
14.2
15.0
15.1
15.2
16.0
Standard Screen ........................................................................... 89
Screen with DMT Settings ................................................................ 91
CCN Playback.exe.................................................................. 93
Changing the Current Time .............................................................. 94
Selectable Chart Options ................................................................. 95
Chart Options (for Single CCN and CCN Playback Programs) ............. 96
17.0 Remote Operation of CCN Programs through a Network Connection
(Remote Desktop) ............................................................................ 97
Appendix A: Glossary ....................................................................... 99
Appendix B: Relationship between SS%, Particle Concentration, and
Percentage of CCN Counted ..............................................................107
Appendix C: Assy, Cable 28V Power ....................................................108
Appendix D: CCN Mounting Hole Locations ...........................................109
Appendix E: CCN Aircraft Inlet (for Constant Pressure Inlet) .....................110
Appendix F: Exploded View of OPC .....................................................111
Appendix G: Sheath Flow Filter Testing and Replacement ........................112
Problem ............................................................................................112
Recommendations ................................................................................112
Appendix H: International Shipping Certification ...................................113
Appendix I: Revisions to Manual .........................................................114
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List of Figures
Figure 1: CCN Counter with Front-Mounted Touch Screen ........................ 11
Figure 2: Supersaturation Being Generated in the CCN Column .................. 14
Figure 3: Air and Liquid Flow Schematic Diagram ................................... 16
Figure 4: CCN with Important Components Labeled ................................. 19
Figure 5: Solenoid Pumps .................................................................. 20
Figure 6: CCN with Shipping Hood on Frame .......................................... 21
Figure 7: Bottle Hold-Down Clamp ....................................................... 23
Figure 8: SS Tab .............................................................................. 25
Figure 9: Location of Power, Communications, Sample and Exhaust
Connections .............................................................................. 32
Figure 10: Controller and Power Supply Boards with LEDs and OPC Switch
Labeled ................................................................................... 34
Figure 11: CDPE Board. ..................................................................... 35
Figure 12: Healthy Desiccant Tube ...................................................... 37
Figure 13: Calibration Set-Up ............................................................. 38
Figure 14: Activation Curve Used in SS% Calibration ................................ 39
Figure 15: Temperature Gradient Curve for Different SS% ........................ 40
Figure 16: Sheath Flow Metering Valve................................................. 41
Figure 17: Accessing Metering Valve Through Port (Newer CCNs Only) ......... 41
Figure 18: Inputs for CCN Flow Calibration Procedure .............................. 42
Figure 19: Sheath Flow Calibration Spreadsheet ..................................... 43
Figure 20: OPC 1st Stage Monitor Voltage ............................................. 46
Figure 21: OPC Mounting Location on Column ........................................ 47
Figure 22: Air Drying OPC with Canned Air ............................................ 48
Figure 23: Nafion Insertion ................................................................ 55
Figure 24: Typical Healthy Membrane .................................................. 55
Figure 25: Typical Bad Membrane. Note the kinks and flat spots. ............... 56
Figure 26: Main Screen of SINGLE CCN Program ...................................... 60
Figure 27: Supersaturation (SS) Settings Tab Display ............................... 61
Figure 28: Dry Start Up and Dry Shut Down Buttons ................................ 62
Figure 29: Supersaturation (SS) Settings Tab Display in Manual SS Mode ....... 63
Figure 30: Temperature Tab Screen Showing Temperature Set Points and
Read-Outs the CCN Temperatures .................................................. 64
Figure 31: Flows Control Tab ............................................................. 68
Figure 32: Optical Particle Counter Tab ................................................ 70
Figure 33: Monitor Tab ..................................................................... 72
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Figure 34: Chart Tab ........................................................................ 75
Figure 35: Program Control Tab .......................................................... 76
Figure 36: Histogram ........................................................................ 77
Figure 37: Time-Series Concentration Chart .......................................... 78
Figure 38: Serial Output Tab .............................................................. 79
Figure 39: DMT Service Tab ............................................................... 80
Figure 40: DMT Service Tab – PID Section .............................................. 81
Figure 41: DMT Service Tab – Gains Section ........................................... 82
Figure 42: DMT Service Tab – FlowCal Section ........................................ 83
Figure 43: DMT Service Tab – Error/Exit Section ..................................... 84
Figure 44: Program for Setting the Supersaturation Tables ....................... 88
Figure 45: CCN Calibration Editor.exe .................................................. 90
Figure 46: CCN Calibration Editor.exe with DMT Tabs .............................. 92
Figure 47: CCN Data Playback ............................................................ 94
Figure 48: Playback Timing Controls .................................................... 95
Figure 49: Using Playback Controls for Zooming ..................................... 95
Figure 50: Selectable Chart Tab.......................................................... 96
Figure 51: Percentage of CCN Counted vs. Particle Concentration for Different
SS% ........................................................................................107
Figure 52: OPC Assembly, Exploded View.............................................111
List of Tables
Table 1: Locations where Water Accumulation and Condensation is Permissible
in CCN ..................................................................................... 18
Table 2: CCN Fuse Listing .................................................................. 53
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PART I: THE CCN INSTRUMENT
1.0
Product Description
1.1 Introduction
The Droplet Measurement Technologies (DMT) Cloud Condensation Nuclei Counter (CCN)
is based on the design of Dr. Greg Roberts of Scripps Institute of Oceanography and Dr.
Athanasios Nenes of Georgia Institute of Technology. The technology is patent pending
and licensed for manufacturing by Droplet Measurement Technologies, Inc.
The CCN measures aerosol particles called cloud condensation nuclei that can form into
cloud droplets. The instrument operates by supersaturating sample air to the point the
where the CCN become detectable particles, which are then sized using an optical
particle counter and distributed into 20 bins. The DMT CCN counter can be operated on
the ground or on aircraft. A photo of the instrument appears in Figure 1.
The CCN control program, Single CCN.exe, offers a graphical user interface at the host
computer. This software provides control of CCN instrument parameters while
simultaneously displaying real-time particle size distributions. Data interfacing is done via
line drivers meeting the RS-232 electrical specifications. Single CCN.exe and other CCN
software programs are described in Part II of this manual.
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Figure 1: CCN Counter with Front-Mounted Touch Screen
1.2 CCN Specifications and Features
Technique:
Measured Particle
Size Range:
Supersaturation Range:
Time Required for
Supersaturation Change:
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Supersaturating aerosol particles in a 50-cm-high
column with continuously wetted walls and a
longitudinal thermal gradient; sizing subsequently
activated particles using an optical particle counter
0.75 – 10 µm
0.07 – 2.0%
~30 seconds for 0.2% change
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Operator Manual, Cloud Condensation Nuclei Counter
Flow Range:
Optical Particle Counter Laser:
Number of Particle Size Bins:
Sampling Frequency:
• Total flow: 200 – 1000 volume cc/min (factory
calibrated at 500 Vccm)
• Sample flow: 20 – 100 Vccm
• Sheath flow: 180 – 900 Vccm
660 nm, 35 mW
20
1 Hz / 1 second
Data System Interface:
RS-232, 9.6 Kb/sec Baud Rate
Data System Features:
• Onboard computer for control and data logging
• Touch screen control and display
• Serial data output for external computer
Calibration:
Comparison of CCN output that of reference
instruments (Differential Mobility Analyzer (DMA) and
a CN Counter)
1.3 Electrical Specifications
Power Requirements:
Current:
28 VDC
15 A at startup, nominal 7 A during regular operation
1.4 Physical Specifications
Size:
Weight:
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For lab use (with frame):
o 35.0” H x 19.3” W x 15.6” D /
o 88.9 cm H x 48.9 cm W x 39.7 cm D
For aircraft use (without frame):
o 32.0” H x 18.4” W x 6.5” D /
o 81.3 cm H x 46.7 cm W x 16.4 cm D
For lab use (with frame): 35.2 kg / 77.5 lb
For aircraft use (without frame): 29.0 kg / 64.0 lb
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Operator Manual, Cloud Condensation Nuclei Counter
Features:
Rack-mount compatible
Center of gravity located 15.5” from bottom of
back base plate
Instrument plumbing system sealed for
operation on pressurized aircraft
1.5 Operating Limits
The CCN operates by maintaining a positive temperature differential between the top of
the column and the bottom. The top of the column always starts at ambient temperature
or slightly above. For high supersaturations, temperature differentials of 20º C or more
are required. Therefore the instrument will perform best if its environmental
temperature is kept as low as possible.
It is not recommended, however, that the CCN be subjected to temperatures below 5 °C.
The Nafion humidifier needs to be kept wet but not freezing. Even if the rest of the
instrument is drained, there is the potential of damage to the Nafion. If the CCN is at
temperatures below freezing, the instrument should be drained and dried as detailed in
section 3.5, and the Nafion humidifier removed from the instrument.
2.0
Theory of Operation
2.1 How the CCN Generates Supersaturation
The CCN counter operates on the principle that diffusion of heat in air is slower than
diffusion of water vapor (Roberts and Nenes, 2005). Inside the column, a
thermodynamically unstable, supersaturated water vapor condition is created as follows.
Water vapor diffuses from the warm, wet column walls toward the centerline at a faster
rate than the heat. Figure 2 shows point C along the centerline where the diffusing heat
originated higher on the column (red-line, point A) than the diffusing mass (blue line,
point B). Assuming the water vapor is saturated at the column wall at all points and the
temperature is greater at point B than at point A, the water vapor partial pressure is also
greater at point B than at point A. The actual partial pressure of water vapor at point C is
equal to the partial pressure of water vapor at point B. The temperature at point C is
lower than at point B, however, which means that there is more water vapor
(corresponding to the saturation vapor pressure at point B) than thermodynamically
allowed.
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Figure 2: Supersaturation Being Generated in the CCN Column
Seeking equilibrium, the supersaturated water vapor condenses on the cloud
condensation nuclei in the sample air to form droplets, just as cloud drops form in the
atmosphere. An Optical Particle Counter (OPC) using side-scattering technology counts
and sizes the activated droplets.
2.2 Details of CCN Design
The CCN column is mounted vertically with the ambient aerosol entering at the top. The
wall temperature along the column gradually increases to create a well-controlled and
quasi-uniform centerline supersaturation. The aerosol sample thus becomes progressively
supersaturated with water vapor as it traverses down the column.
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The sample is placed at the center of the column where supersaturation is highest, and
filtered humidified sheath air surrounds the sample. The recommended flow ratio is 1
part of sample air to 10 parts of sheath air. This ratio ensures that the aerosol is exposed
to a uniform supersaturation profile. The CCN’s vertical mounting, cylindrical geometry,
and a porous alumina bisque liner (which provides the wetted surface down the column
wall) minimize buoyancy effects and help droplets grow to detectable size.
At any given point in time, the CCN unit operates at a single supersaturation. This is
because the temperature and water vapor gradient along the wetted walls are
approximately constant along the wall. As shown by Roberts and Nenes (2005), the
centerline supersaturation depends on the temperature difference between the top and
bottom of the column, the flow rate, and the absolute pressure in the column.
A unique feature of the instrument is that the column has three temperature control
zones, with the temperature increasing from the top zone to the bottom zone. This
allows supersaturation to occur and also allows for rapid shifting between
supersaturations. Software controls allow the user to change from one supersaturation to
another, and the supersaturation can be varied between 0.07% and 2%. Approximately 30
seconds is required for a supersaturation shift.
The total variable airflow rate through the column is from 200 to 1000 volume cubic
centimeters per minute (Vccm), with the recommended total flow being 500 Vccm. The
column operates in laminar flow. The sheath flow is generated in the instrument by
taking a portion of the sample air, filtering it, and humidifying it before it is used as
sheath in the column.
Activated droplet counting is done with an Optical Particle Counter (OPC). The OPC has
been specially designed for the CCN and uses side-scattering technology for the particle
sizing. A diode laser with a wavelength of 660 nm is used as the light source. The sizing
range for activated particles is 0.75 to 10 µm, and particles are distributed in 20 size
bins. The first bin stores detectable particles up to .75 µm, while the second stores .75 –
1.0 µm particles. After that, the bin widths are.5 µm (1.0 - 1.5 µm, 1.5 – 2.0 µm … 9.5 –
10.0 µm). The wide sizing range and multiple binning of the OPC provide additional
details on the growth of particles as well as information about how well the instrument is
functioning. Particle sizing data is updated at 1-second intervals.
For information on how the supersaturation rate affects the maximum particle
concentration, see Appendix B.
2.2.1
Flow of Air and Water through the CCN
Figure 3 shows a flow chart of how air and water pass through the CCN. For a photograph
of individual instrument components on the instrument, see Figure 4.
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Figure 3: Air and Liquid Flow Schematic Diagram
The inlet manifold serves as the connection point for the sample flow, sheath flow,
bottle vents, and the absolute pressure transducer for the sample pressure measurement.
Sample flow is measured by pressure drop across the capillary (4) with a differential
pressure transducer. The sample air proceeds directly into the top of the growth column
(6).
The sheath airflow is split off of the sample flow (9). The sheath air passes through a
metering valve, which applies resistance to regulate the ratio between the sample and
sheath air. The ideal flow ratio is 10 parts of sheath air to 1 part of sample air. Note that
only the total airflow in the CCN is regulated; this is done through the proportional valve
(24). Absolute flow to the sample and sheath flows is controlled by adjusting both the
total air flow and the sample-sheath flow ratio.
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After the sheath air travels through the metering valve, it passes through a filter (12) and
a frit element with a differential pressure transducer for the flow measurement (13/14).
The sheath air is then passed through the outside of the Nafion Perma-Pure unit to
humidify the air (15). The Nafion is maintained close to the temperature of the top of the
column. This ensures that minimal change is needed to reach the dew point at the top of
the column.
The air in the column passes through the Optical Particle Counter (OPC) (22). A closed
loop air-drying system is used for the OPC. If water droplets should enter the OPC, these
are removed out the drain on the bottom of the OPC and collected in the water trap (29).
The air then cycles through the OPC pump, drying column, and filter (19-21) before being
put back into the OPC. This ensures that the OPC will not fog if operated on an aircraft.
The displacement of the OPC pump is 60 µl per cycle, and the pump is controlled
independently of the computer. However, this pump in the CCN counter operates only
when the TEC relay power is turned on.
After the air in the column passes through the OPC, it enters a cold trap (18). This drops
the dew point of the air so that water will not condense in the proportional valve (24) or
sample pump (25). As stated above, the proportional valve regulates the total airflow
through the CCN. The computer measures the total airflow and this data is fed back to
the proportional valve.
A diaphragm pump (25) is used to provide system vacuum and then vents the air out the
exhaust port on the side panel (26). The entire system is sealed so that the unit can
operate in a pressurized environment. When operating at reduced pressures, it is
necessary to vent the exhaust port at a pressure close to the inlet pressure.
The water supply and drain bottles are connected to the inlet manifold to equalize
pressure for the supply and drain (27, 28). The water supply is fed with a solenoid pump
(16) through the center of the Nafion and then to the top of the column (11) to supply
humidification water. Solenoid pumps (23, 28) are also used to remove excess water from
the bottom of the column and the cold trap. Each of these pumps has a flow capacity of
60 µl per cycle.
WARNING
Do not allow unit to run when supply water bottle is
empty, or unit may not function properly when water is
added.
Table 1 shows locations along the air and water flow paths where water and water
condensation are to be expected.
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Location No.
I
2
3
4
5
6
7
8
9
10
11
12
Air Flow Path: No water should ever be present here.
Pressure Measurement Port: No water should ever be present here.
Pressure Measurement Port: No water should ever be present here.
Sample Air Flow Path: No water should ever be present here.
Pressure Measurement Port: No water should ever be present here.
Sample Air Flow Path: No water should ever be present here.
Bottle Vent: No water should ever be present here.
Bottle Vent: No water should ever be present here.
Sheath Air Flow Path: No water should ever be present here.
Sheath Air Flow Path: Condensation Present.
Water Supply: Water should always be present here.
Sheath Air Flow Path: No water should ever be present here.
13
Pressure Measurement Ports: No water should ever be present here.
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
Pressure Measurement Ports: No water should ever be present here.
Sheath Air Flow Path: No water should ever be present here.
Water Supply: Water should always be present here.
Water Drain: Water should be intermittent here.
Air Flow Path: Condensation Present.
OPC Dry Purge Air: No water should ever be present here.
OPC Dry Purge Air: May have condensation.
OPC Dry Purge Air: May have condensation.
OPC Dry Purge Air: May have condensation.
Water Drain: Water should be intermittent here.
Air Flow Path: No water should ever be present here.
Air Flow Path: No water should ever be present here.
Air Flow Path: No water should ever be present here.
Water Supply: Water should always be present here.
Water Drain: Water should be intermittent here.
OPC Water Trap Bottle: May have condensation and 1 or 2 drops of water.
Nafion block drain: No water should ever be present here.
Table 1: Locations where Water Accumulation and Condensation is Permissible in CCN
2.2.2
CCN Components
Figure 4 shows the important components of the CCN. Figure 5 and Figure 12 show
solenoid pumps and the desiccant tube, respectively; these components are hidden in
Figure 4.
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Figure 4: CCN with Important Components Labeled
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Figure 5: Solenoid Pumps
3.0
Setting up the CCN
Several steps are required for initial CCN set-up:
Unpacking and mounting the instrument
Connecting CCN components such as the power cables, supply and drain bottles,
and touch screen monitor
Setting the flow and humidifying the instrument (humidification can take up to 12
hours and must be performed every time the CCN is dry when started)
Checking that the CCN is functioning properly
These steps are described in detail in the following sections.
Any time the CCN is shipped, it must be dried out and properly repacked prior to
shipment. Failing to follow proper procedure will result in damage to the instrument. See
sections 3.4 and 3.5 for details.
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3.1 Unpacking the CCN
3.1.1
Removing Instrument from Shipping Case
To minimize the potential for damage in shipping, the CCN arrives on a 36” x 36” custom
pallet with a fitted case, special frame, and protective hood (Figure 6). The frame can be
substituted as a bench stand for the unit. To remove the instrument from the case,
follow the steps below.
Figure 6: CCN with Shipping Hood on Frame
1. Cut straps securing case to pallet and save pallet.
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2. Lift the CCN unit out of the case, using the back bar on the stand as a handle.
3. Remove two bolts on the underside of the hood. These bolts go through an angled
aluminum bracket into the upright side of the frame, and there will be one bolt on
either side.
4. Hold the shipping hood and pull up the two head bolts that go through the
aluminum strap into the frame. The bolts are essentially pins that can be pulled
straight up.
5. Inspect the CCN for shipping damage.
6. If the CCN is to be mounted in a different rack, remove the CCN from frame.
7. Save parts for return shipping.
3.1.2
Connecting Instrument Components
1. Connect the power cable to the instrument. The power cable (ASSY-272) supplied
in the startup kit is already installed and pretested on the bench top AC/DC power
supply, which is also in the kit. The white wire (labeled “+28V”) connects to +28V
VDC and the black wire (labeled “RETURN”) connects to the return of the power
supply. If a longer cable is being used, refer to Appendix C. Check the polarity of
the power before connecting the instrument.
WARNING
THE CCN COUNTER IS NOT REVERSE POLARITY PROTECTED AND WILL BE SIGNIFICANTLY
DAMAGED BY INCORRECT WIRING.
Warning
Make sure the CCN Main Power is OFF prior to connecting or disconnecting any external
power or I/O Cable
2. Remove the front cover from the instrument. There will be 12 screws around the
perimeter of the instrument, and 3 on the left side into the connection panel.
3. Unpack the supply bottle, drain bottle, bottle hold-down clamp, and clamp screw.
These are packed separately from the main CCN instrument in the start-up kit.
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The supply and drain bottle caps have been packaged in a plastic bag and tied to
the frame. Remove the tie and bag.
4. Install the drain bottle in the bottle holder. The best location for the drain bottle
is in the rear of the two slots in the bottle tray. See Figure 7.
5. Fill the supply bottle with distilled or deionized water and set it in the front of
the bottle tray.
6. Make sure the bottle caps are tight on the bottles. Otherwise, air will leak into
the inlet system.
7. For airborne applications, install the bottle hold-down clamp. See Figure 7.
Figure 7: Bottle Hold-Down Clamp
8. If desired, mount the touch screen to the front of the CCN case:
a. Remove the two Phillips-head screws that hold the tripod leg to the back
of the screen. This will expose the back of the screen and the location of
the four mounting holes.
b. Remove the four hole plugs from the front of CCN case.
c. Connect the cables to the screen.
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d. Mount the screen to the case, using the four 4.7 mm screws with lock
washers that are provided in the startup kit.
e. Save the parts that were removed from the screen and the case.
9. Connect the touch-screen video and serial cables to the side panel. Turn on power
to the touch screen either from the external power supply or from the side panel,
using the cable provided.
10. Set the cover back on the guides at the top of the CCN chassis. Do not secure the
cover screws yet, however, as flow adjustments need to be made (see section
3.2).
11. Remove plugs from inlet and outlet fitting on the side of the unit.
3.1.3
USB Memory Stick
A USB memory stick is tie-wrapped and attached with Velcro to the CCN exhaust line. The
memory stick should be stored in this location, as it contains important information about
the instrument:
White papers describing the theory behind the CCN design
A copy of the CCN manual
Detailed spreadsheets for use in instrument calibration
LabVIEW software programs used to operate the CCN
3.2 Setting Flow and Humidifying CCN
1. If you have not already done so, install the drain and supply bottles on the CCN.
The supply bottle should be filled with distilled or deionized water.
2. Start the CCN. The breaker on the side panel also serves as the power switch. The
computer will load the Single CCN.exe control program and start automatically.
3. During the first 10 seconds after the program starts, click the Dry Start Up button
shown in Figure 8. Selecting Dry Start Up will set the liquid supply pump to high
and disable the CCN concentration alarm.
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Figure 8: SS Tab
4. On the main CCN window, go to the Flows tab.
5. The flow ratio between the sheath and sample flow is displayed directly in the
center window. Adjust the green knob on the sheath flow metering valve (see
Figure 4) until this ratio reads 10.0 +/- 0.3.
6. Check the position of the OPC drying system time switch. This switch controls the
solenoid pump in the drying system. The switch is labeled SW1 and is located in
the middle of the Controller Printed Circuit Board, as shown in Figure 10. The
solenoid pump can cycle every 2 seconds or every 16 seconds. Set this switch to
the 16-second position.i
7. After the column is fully wetted, the OPC should be counting. Note that it may
take 4 to 12 hours for the CCN to become properly humidified and count particles.
At this time, all the status lights on the monitor tab should be illuminated (Figure
33). Illuminated status lights indicate the CCN Instrument is functioning properly.
You can now begin to collect data.
i
1. In general, the switch should be set to the 16-second position, because when the pump
operates every 2 seconds water may infiltrate the CCN without generating an alarm. However,
the 2-second position is recommended in certain circumstances. It is useful in airborne
applications where altitude changes can cause migration of saturated water vapor into the OPC.
In addition, if the OPC has fogged, switching to the 2-second position will speed the removal of
water vapor. (The switch should be returned to the 16-second position after the fog has
dissipated.) For more details on the OPC drying system, see section 2.2.1.
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If any of the Monitor tab status lights are not illuminated, there is an issue with
the CCN instrument and it should not be run until problem is corrected. Copy the
latest data file from C:\CCN DATA. Shut off power to the CCN instrument and send
the data file to DMT at CCN-INFO@dropletmeasurement.com.
8. Re-Install the cover on the CCN.
3.3 Checking that the CCN is Functioning Properly
The following test should be performed before using the CCN for the first time. It should
also be done whenever instrument performance needs to be verified. Note: The
procedure below assumes you have already started up the CCN as described in the
previous section.
1. Install the filter provided on the inlet of the CCN. Operate the instrument for 15
minutes, then monitor the number of counts. Total counts should be less than five
per second.
2. Connect a volume displacement flow meter (Gilian, Buck, or laboratory
constructed) to the inlet of the CCN.
3. Note the total flow on the Flows tab.
4. Measure the flow with the displacement flow meter.
5. Repeat step 4 five times. The average measured flow should be ±10% of the stated
flow on the Flows tab.
6. Remove the filter from the inlet of the CCN and set the following supersaturation
gradient scans:
Supersaturation Setting
Duration of Scan
0.2%
10 minutes
0.4%
5 minutes
0.6%
5 minutes
0.8%
5 minutes
1.0%
5 minutes
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Run two complete supersaturation cycles. As the supersaturation increases, verify
that the number concentration of particles measured remains stable or increases.
3.3.1
Testing the Unit for Leaks (for CCN Use on Pressurized Aircraft)
If CCN unit will be installed in pressurized aircraft, perform the following leak test in
addition to the zero-count check described in section 3.3.
1. Install a valve or plug on the inlet of CCN unit while it is running.
2. Allow the unit’s internal air pump to evacuate the system. This may take several
minutes. Monitor the progress on the Flows tab’s Sample Pressure field.
3. When the unit has pumped down below approximately 400 mb, go into the Flows
tab and turn off the Air Pump. This will turn off power to the pump, which will
also act as a seal.
4. If unit does not pump down below 400 mb, there is a leak that needs to be fixed
prior to retesting.
5. Wait 60 seconds to allow pressure to stabilize, and then monitor how fast the
sample pressure rises. Typically 5 mb or less per second is good.
6. If unit leaks at an unacceptable rate, try isolating and fixing leak then retest using
above method.
7. To shut down the CCN, always start by shutting down the control program. Go to the
Prog tab and press the Shutdown button. You can then simply turn off the main power
switch on the side of the unit. You can also close Windows first by turning off the
computer and then turning off the power switch on the side of the unit when the
screen goes blank.
Note:
Most leaks are operator induced.
Bottle caps need to be tightened fully to seal properly.
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Warning
Use extreme care in preventing water from entering the inlet to the CCN
counter. Liquid water will plug the sheath air filter and shut off flow. If
liquid water does enter the inlet:
IMMEDIATELY SHUT OFF THE INSTRUMENT.
If a small amount of water (less than a few ccs) has entered, disconnect
the pressure transducer and sample inlet fittings from the inlet manifold
and dry the manifold using warm air and replace the filter on the sheath
air.
If additional water has entered the system,
contact Droplet Measurement Technologies immediately.
Warning
The CCN Counter must be prepared for shipping by drying the column and
draining the OPC (see Section 4.0).
3.4
Repacking the CCN for Shipping
1. Ensure that the CCN is dried prior to shipping (see Section 3.5).
2. Bolt the CCN to the frame, installing four bolts on each side at the 1, 3, 4, and 5
positions as counted from the top of the frame.
3. Install the shipping hood over the front of the case, and insert the bolts through
the top straps into the frame.
4. Insert the bolts into the number 2 position on each side of the frame through the
angled brackets on the hood.
5. Slide the CCN unit into the case, noting the orientation. The back of the CCN
frame goes toward the side of the case with the extra foam block.
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6. Attach the top half of the case, noting the orientation of the case halves.
7. Strap the case to a pallet whenever shipping the CCN commercially in order to
ensure instrument safety. (The pallet size is 36” x 36” if you did not save original
shipping pallet.) This prevents dropping and turning the case upside down.
Please Note:
To Ensure Safe Shipment of CCN:
CCN must be strapped and shipped on original CCN Pallet
If CCN is returned to DMT NOT on a CCN pallet:
You will be charged for a new CCN pallet
COST: one hundred dollars ($100.00) per pallet
3.5 Drying the CCN Prior to Shipping
3.5.1
Necessity of Drying CCN
The CCN can collect liquid water in the reservoir around the OPC and in the cold trap.
This water is continually removed by the drain pump and pumped into the drain bottle. In
normal operation, small amounts of liquid water in these areas will not cause a problem,
as they will not migrate into the OPC. If the unit is shipped with liquid water in these
areas, however, it can migrate into the OPC if the instrument is inverted or handled
roughly in shipping.
3.5.2
To Drain All Liquid Water
Prior to shipping the CCN, drain all liquid water from the OPC and cold trap by the
following these steps:
1. Start the Single CCN.exe program.
2. Click Dry Shut Down button during the first 10 seconds after the program starts.
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3. When the system instructs you to do so, shut down the sheath flow metering
valve. The liquid supply pump will be turned off and the drain pumps will be
turned on high. The flow total flow will be set to 175 Vccm. The CCN
concentration status and flow status alarms will be disabled. After 6 hours, the
unit will turn off the control program and display a message that the unit is dried
out and ready to ship.
4. Remove the supply, drain bottles, bottle hold-down clamp and screw.
5. Place the bottle caps in a plastic bag and secure them to the frame above the
supply pump with a cable tie wrap.
The instrument can now be mounted on the frame for shipping.
4.0
Installation
4.1 Power Supply Considerations
The CCN is designed to operate on 28 VDC power. Ground-based applications require a
line voltage to 28 VDC supply, which can be either a linear or switching supply. The
capacity of the supply should be at least 15 A. The CCN may draw this current load for up
to a few minutes at startup, and then will typically draw 6-10 A in normal operation.
A recommended power supply is a V-Infinite (#VPM-S500-24R) preset to 28 V. This unit
has a wide input range that has been successfully used with the CCN.
The quality of 28 VDC on aircraft varies considerably. If there are high frequency spikes
when the 400 Hz power is converted to 28 VDC, this can cause problems with the CCN. If
problems occur when operating the CCN in an aircraft environment, check the line
voltage to 28 VDC supply.
For more information on power and signal connections, see section 5.0.
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5.0
CCN Power and Signal Connections
The CCN’s power, signal and exhaust connections are located on the side of the
instrument, as Figure 9 illustrates.
Power is applied to the CCN through a military-style circular connector, Model PT06A-124S (SR). The power on this connector is split into two 28 VDC legs of which all four pins
must be used:
Pins A and C: +28 VDC
Pins B and D: Power Return.
12 awg wire must be used between the power source and the power connector. The
white wire is positive and the black wire negative on all DMT-supplied cables. See
Appendix C for details.
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Figure 9: Location of Power, Communications, Sample and Exhaust Connections
The MAIN POWER switch is a 20-Amp circuit breaker for protection of the CCN
instrument.
The pilot light (see Figure 9) indicates if instrument power is ON or OFF.
The data communication connectors are as follows:
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Video: Connection for video monitor, either the touch screen supplied with the
instrument or any standard video monitor. Resolution for an external monitor
needs to be set at 600 x 800.
Screen Power: 12 VDC power output for the touch screen. The cable is supplied
with the CCN.
Touchscreen: The serial port connection for the touch screen cursor operation.
Data Out: The main serial port. Serial data output is RS-232, 9600 baud, 8-N-1. A
null modem must be used in connecting to the serial port on external computers
for correct communication.
Keyboard: The standard keyboard connection. This can be used with the touch
screen or with a standard monitor.
Mouse: The mouse connection, which is active with the touch screen or a
standard monitor.
USB: USB 1.1 port for auxiliary USB devices.
ETHERNET: A standard network connection.
The SAMPLE and EXHAUST connections are ¼ inch Swagelok connections.
If the CCN is being operated in a pressurized aircraft, the EXHAUST port must be
connected to an overboard dump. A leak check should also be performed on the CCN
before operating in a pressurized cabin; see section 3.3.1. Leaks that were not apparent
prior to pressurization may be come problematic in a pressurized cabin.
6.0
Printed Circuit Boards (PCBs)
The CCN’s controller, power supply, and CDPE boards are located to the left of the Nafion
block, as shown in Figure 4. Figure 10 shows a close-up of the controller and power supply
boards, while Figure 11 depicts the CDPE board.
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Label
A*
B
C
D
E
What Illuminated LED Indicates
28 V power is present in unit
5 V power supply on Power Supply Board is present
12 V power supply on Power Supply Board is present
5 V power supply for computer is present
Watchdog pulse is present (blinks at 1 Hz in tandem with watchdog
light)
F
Power is supplied to cold trap—will cycle around
G
5 V power supply on Controller Board is present
H
12 V power supply on Controller Board is present
I
Power is supplied to Nafion heater
J
Power is supplied to inlet heater
K
Power is supplied to OPC heater
L*
TEC Relay is ON
* Labelled "L1" on board. (Most LEDs are unlabeled on the boards themselves.)
Figure 10: Controller and Power Supply Boards with LEDs and OPC Switch Labeled
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Figure 11: CDPE Board. D1, D2, and D3 are lit all the time when there is power supplied to the instrument.
7.0
CCN Maintenance
DMT recommends the following service and maintenance schedule for the CCN. The
maintenance schedule is based on the continuous operation of the instrument and may
need to be modified for other operating conditions.
7.1 Every 4 days and Before Every Flight
1. Empty the water bottles. The water in these bottles is not hazardous since it has
only been exposed to ambient air, so it can be disposed of in any drain. Check
area for leakage.
2. Check OPC water trap for any liquid removed from the OPC. If liquid is present,
empty the bottle.
3. Check the bottom of case for any water leakage, as this would indicate leakage of
the liquid flow system.
4. Refill the supply bottle with clean deionized or distilled water. This water can be
procured at a grocery store. However, it is important that the water not be
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artesian water or any water with added minerals. The water consumption rate
is as follows:
4.8 ml per hour when Liquid Flow Set (on Flows tab) is low
7.2 ml per hour when Liquid Flow Set is medium
18.0 ml per hour when Liquid Flow Set is high
5. Make sure the caps on both bottles are securely tightened. If caps are not
tightened securely, the air stream can become contaminated.
7.2 Every Month
1. Check the filters on the air inlets at the right-hand side of the case. If filters are
dirty, wash and replace them.
2. Check the calibration on sheath and sample airflows.
3. Check the desiccant tube for the OPC dryer. Replace the tube if necessary,
replacing the filter and dryer unit at the same time. Healthy desiccant tubes
should have a deep orange indicator gel, as shown in Figure 12. Lighter orange
gels indicate the tube needs to be replaced.
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Figure 12: Healthy Desiccant Tube
7.3 Every Three Months
Replace the sheath airflow filter. Note: The sheath flow filter may need to be replaced
more frequently in high-concentration environments or if the filter is passing particles.
Sheath flow filters can be susceptible to leaks; see Appendix G.
7.4 Every Year
1. Calibrate the internal temperature curve of CCN by comparing CCN data to that
generated by a Differential Mobility Analyzer (DMA) and CN counter. See section
8.1 for details.
2. Clean and calibrate the OPC.
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3. Replace the Nafion humidifier membrane.
4. Calibrate the Absolute Pressure Transducer.
7.5 Pump Diaphragm and Motor Maintenance Requirements
A pump failure will not cause any damage in the CCN, so it is acceptable to wait until the
pump fails fail to replace the diaphragm and motor. These can also be replaced when their
estimated lifetime expires. The pump diaphragm lifetime is approximately 4000 hours, while
the pump motor lifetime is approximately 8000 hours.
8.0
Calibration Procedures
For optimum CCN performance, periodically calibrate the CCN flow sensors, pressure
transducers and the optical particle counter. See the sections below for details.
8.1 CCN SS% Calibration
8.1.1
Recommended calibration equipment
Aerosol Generator System for nebulizing ammonium sulfate particles (DMT Aerosol
Generator AG-100))
Differential Mobility Analyzer (TSI3080L or equivalent)
CN Particle Counter (TSI3025L or equivalent)
Refer to Figure 13 for the calibration set-up.
Figure 13: Calibration Set-Up
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The CN Counter is used as a reference instrument. It will count 100% of all the particles
that are fed into it from the DMA. The ratio of the number of particles the CCN could
count if they activated can now be determined.
8.1.2
SS% Calibration Procedure
The CCN temperature is tested with gradients of 3, 4, 6, and 8. The 50% activation point
(Figure 14) for that size of ammonium sulfate is converted from the Köhler curve to a
SS%. A linear regression between the measured SS and the temperature gradient is run on
the data and that becomes the SS% calibration curve for the CCN instrument (Figure 15).
The curve is very linear down to 0.1%. Running SS% below 0.1% will require special
calibration and interpretation. (Below 0.1% SS growth kinetics become very important
and can influence the data.)
Calibration parameters:
Sample Flow Rate:
Sheath Flow Rate:
Sheath:Sample Flow Ratio:
45 Vccm
450 Vccm
10:1
Figure 14: Activation Curve Used in SS% Calibration
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Figure 15: Temperature Gradient Curve for Different SS%
8.2 Flow Calibrations
8.2.1
Recommended Calibration Equipment
Volumetric displacement flow meter (the range should be from 10-1000 Vccm)
USB stick that accompanies the CCN (this contains initial factory calibration data
to be used as a reference, as well as a spreadsheet to run the regression analysis)
8.2.2
Flow Calibrations Procedure
Sample flow calibration:
1. Connect the volumetric displacement flow meter to the inlet port on the side of
the CCN instrument.
2. Close the sheath flow metering valve. If you have a unit built before fall of 2011,
you will need to remove the instrument cover to access the green sheath flow
metering valve (Figure 16). If you have a newer unit, you can access the valve
through an access port (Figure 17).
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Figure 16: Sheath Flow Metering Valve
Figure 17: Accessing Metering Valve Through Port (Newer CCNs Only)
3. In the CCN software, click on the DMT Service tab. Click just below the text
window in the middle of the screen. In the white text box that appears, type in
the password Service. Then select the FlowCal sub-tab.
4. Change Sample Flow y-int to 0 and Sample Flow slope to 1.
5. Go to the Flows tab on the CCN control window and turn on the Manual Override.
Button. Using the Valve Set M (V) field, adjust the valve voltage until the sample
flow as measured on the external flow meter (not on the computer display) is
approximately 75 Vccm.
6. Record the flow from the flow meter in the flow column of the spreadsheet. Next,
record the value displayed in the Sample Flow (Vccm) field in the volts column.
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(Because Step #4 sets the regression coefficients to 1 and 0, the Sample Flow
(Vccm) indicator is now actually displaying the voltage from the sample flow
differential pressure transducer.) This value typically ranges from 2.3 to 4.0 V. Do
not record the Valve Set M (V) value for use in the regression. (You can record it
for informational purposes, if you want to remember which settings are used to
achieve specific flow rates.) See Figure 18.
Figure 18: Inputs for CCN Flow Calibration Procedure
7. Repeat steps 5 and 6 for measured flow values on the flow meter of
approximately 60, 45, 30, and 20 Vccm.
8. The Excel spreadsheet should run the regression for you. Verify that r2 > .99.
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9. Insert the new slope and intercept coefficients into the DMT Service tab, in the
FlowCal tab. Use the measured flow meter data as the Y value and the voltage
measurement as the X value. Click Save.
10. Adjust the valve voltage to get a sample flow reading of 45. Verify the Sample
Flow (vccm) reading on the Flows tab agrees with the external flow meter before
proceeding to sheath flow calibration.
Sheath flow calibration:
1. If you have not already done so, connect a flow meter to the flow inlet.
2. Completely open the sheath flow metering valve.
3. In the CCN software, click on the DMT Service tab. Then click just below the text
window in the middle of the screen. In the white text box that appears, type in
the password Service. Then select the FlowCal sub-tab.
4. Change Sheath Flow y-int to 0 and Sheath Flow slope to 1.
5. Go to the Flows tab on the CCN control window and turn on the Manual Override,
if it is not already on. (See figure above.) Using the Valve Set M (V) field, adjust
the valve voltage until the sheath flow as measured on the external flow meter
(not on the computer display) is approximately 750 Vccm.
6. If you have not already done so, open the spreadsheet located on the USB memory
stick you received with the CCN. Measure the actual flow with the flow meter.
Record the total flow from the flow meter in the “total” column of the
spreadsheet. See arrow 1 in Figure 19. Record the displayed sample flow in the
“sample” column (arrow 2). The spreadsheet will automatically calculate sheath
flow (sheath flow = total flow – sample flow).
3
2
1
Figure 19: Sheath Flow Calibration Spreadsheet
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7. Record the value displayed in the Sheath Flow (Vccm) field in the volts column
(arrow 3 in Figure 19). (Because Step #4 sets the regression coefficients to 1 and
0, the Sheath Flow (Vccm) indicator is now actually displaying the voltage from
the sheath flow differential pressure transducer.) Do not record the Valve Set M
(V) value for use in the regression. (You can record it for informational purposes,
if you want to remember which settings are used to achieve specific flow rates.)
8. Repeat steps 5 – 7 for measured flow values on the flow meter of approximately
600, 450, 300, and 200 Vccm.
9. The Excel spreadsheet should run the regression for you. Verify that r2 > .99
10. Insert the new coefficients into the DMT Service tab, in the FlowCal sub-tab. Use
the flow data as the Y value and the voltage measurement as the X value. Click
Save.
Verification and Reassembly
Click the Manual Override button off. Ensure the flow is set to 500 Vccm and the flow
ratio is 10.0 ±.25. Measure the actual sample and sheath flows with flow meter and
compare to the displayed values on the CCN. They should be within 5% of each other. If
not, repeat calibration procedure. Once calibration is complete, reinstall the CCN cover
if you have removed it.
8.3 Pressure Calibration
8.3.1
Recommended calibration equipment
Pressure transducer with a range from 100-1000 mb.
Vacuum pump for applying test vacuum to system.
8.3.2
Pressure Calibration Procedure
1. Following the flow calibration, disconnect the pressure transducer line from the
inlet manifold. Depending on the connection to the vacuum system, adapt or
remove the fitting from the end of the pressure transducer line and connect to
the vacuum source.
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2. Start the CCN counter, and calibrate the pressure transducer at 5 or more points
over the range 100-1000 mb.
3. Reconnect the pressure transducer line to the inlet manifold.
4. Run a linear regression on the calibration and insert the coefficients into the CCN
Calibration Editor.exe program. The pressure data will be the Y values and the
voltages the X values.
5. Replace the cover on the CCN instrument.
8.4 OPC Calibration
8.4.1
Recommended Calibration Equipment
Aerosol generator system for nebulizing polystyrene latex (PSL) particles, such as
the DMT aerosol generator.
PSL calibration particles, 2.0 micron.
8.4.2
OPC Calibration Procedure
1. Start the CCN counter and turn off the liquid supply pump.
2. Set conditions for a low supersaturation of 0.1%, and start the airflow rate.
3. To speed the drying process, use a drying tube such as a Drierite tube. Connect
this to the inlet or, if a drying tube is not available, use air and run the CCN for
about 15 minutes to reduce the humidity in the tube.
4. Connect the aerosol generator to the sample inlet and start the aerosol generator.
5. Note the bin where the calibration particles are measured. A good calibration
exists if the particles are in the proper bin or slightly high. If the particles are in a
lower size bin, the OPC could be dirty and will need cleaning and recalibration.
Contact Droplet Measurement Technologies Inc.
6. Restart CCN for normal operation.
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8.4.3
OPC Cleaning Procedure
After running the OPC dry air recirculation pump on high for 12 hours, if the 1st stage
monitor voltage is still at or near 5.0V, there may be water droplets on the window
between the laser and OPC. The 1st Stage monitor voltage is displayed in the bottom right
of the OPC tab, as shown in Figure 20.
Figure 20: OPC 1st Stage Monitor Voltage
The best way to check and correct this problem is to dry the OPC with canned air, as
described below. Contact DMT before performing this procedure.
1. While the unit is on and the air pump is off, monitor the voltage of the 1st Stage
Monitor.
2. Remove the two 2-56 screws holding the Beam Dump to the OPC block (Figure
21).ii
ii
Appendix E contains an exploded view of the OPC that may be useful when following these
steps.
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WARNING:
When Beam Dump is removed the laser beam will come out of the OPC
through this opening.
DO NOT LOOK DIRECTLY INTO THE OPENING OF THE LASER BEAM.
3. Note the beam dump orientation (wedge points down towards inside of OPC) and
make sure its o-ring (2-011/OR011) is accounted for.
Figure 21: OPC Mounting Location on Column
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4.
Turn power off to unit. Insert the tube on the end of an inert dusting gas (such as
Tech-Spray, Envi-ro-tech 1671 Duster) about halfway into the Beam Dump
opening.
5.
Give a couple of short burst of clean dry air (Figure 22). If there is excessive water
in the OPC, you will notice water mist coming back out of the hole as you spray
into it. Keep applying short bursts until no water mist comes out.
6.
Turn power back on and verify 1st Stage Monitor Voltage has returned to normal
operating value (.2-.4).
7.
Repeat if necessary. Contact DMT for further help if normal operating value
cannot be achieved.
Figure 22: Air Drying OPC with Canned Air
8.
9.0
Reinstall the Beam Dump, ensuring that the o-ring is in place and the orientation
is correct.
CCN Accessories
9.1 Spares and Consumable Supplies
A series of spares and a consumable supplies kits are available for the CCN unit.
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Startup Kit (KIT-0001):
This kit, which is provided with the initial
instrument purchase, contains all the parts
needed to operate the instrument initially.
Major items include bottles, power supply
cables, touchscreen hardware, etc.
Consumables Kit (KIT-0002):
This maintenance kit will support the CCN for
one year of continuous operation. Major items:
4 sheath filters
1 Nafion membrane
1 pump diaphragm repair kit
Spare Parts Kit (KIT-0003):
This kit contains items that could fail and need
replacement. Major items:
4 Thermo-electric coolers (TECs) for column
1 80-GB hard drive preloaded with
instrument calibration
1 current control module for TECs
1 desiccant tube
1 air pump
1 Solenoid pump
Spare Electronic Repair Kit
(KIT-0004):
This kit contains electronic items that could fail
and need replacement. Major items:
1 Power supply PCB
1 Control PCB
1 OPC and OPC control electronics
1 80 GB-hard drive preloaded with
instrument calibration
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This kit has a completely assembled computer
including 80-GB SS hard drive preloaded with
instrument calibration. Major items:
Spare Computer Kit
(KIT-0023):
1 1-GHz computer
1 PC-104 A-D card
1 2 Com port card
1 80-GB hard drive preloaded with
instrument calibration
9.2 Airborne CCN Inlet Assembly Kit
The Airborne CCN Inlet Assembly Kit (AAA-0086) offers accessories that are useful during
aircraft operation. The Constant Pressure Inlet is also useful during ground operation
when the ambient pressure must be controlled.
CCN Rail Mount
(ASSY-0186):
The rail mount provides a secure seat for the
CCN on the aircraft.
CCN Aircraft Inlet
(ASSY-0134):
This supplies the aircraft inlet tubes
outside of the aircraft) and the
plumbing to connect to the Constant
Inlet. See Appendix E for a diagram of
Aircraft Inlet.
Constant Pressure Inlet
(AAA-0087):
This device allows users to control and change
the ambient pressure under which the CCN
operates.
(on the
required
Pressure
the CCN
10.0 Troubleshooting
Problem
“Duplicate file name” light
is yellow.
“Laser Current Status” light
is yellow.
Possible Cause
Battery on computer is
dead and time is same
every time computer
reboots
Laser
Current
has
exceeded
maximum
normal operating life
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Replace battery for computer.
Contact DMT for OPC repair and replacement.
If the laser is still on, unit is working properly.
The laser is near the end of its life, however,
and a replacement should be planned soon.
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Operator Manual, Cloud Condensation Nuclei Counter
Possible Cause
Solutions
OPC is not communicating
with computer
Determine if OPC, wiring, or the computer is
causing the communication issue. It may be
necessary to test OPC with DMT PADS
software. Contact DMT for further instructions.
“1 Stage Monitor Voltage
Status” light is yellow, or 1st
Stage Monitor Voltage is
too high
OPC fogged or flooded
Run OPC dry air recirculation on high for 12
hours. If this does not clear the problem, refer to
Section 8.4.3 for further instructions.
“Flow
yellow.
Sheath filter restricted or
wet, sheath flow valve
closed.
Replace sheath filter, and open sheath valve.
“Temp Control Status”
light is yellow or red.
Blown fuse
Check appropriate fuse. Contact DMT for
further information.
“Sample Temp Status” light
is red or yellow.
Ambient temp is out of unit
range. Sample Temp
Senor malfunction.
Operate unit in range. Contact DMT for further
information.
“OPC Status” light is yellow
or red.
OPC flooded
Determine why OPC flooded, fix the problem,
then run OPC dry air recirculation on high for 12
hours. If this does not clear the problem, refer to
Section 8.4.3 for further instructions.
“Column Temps Stabilized
Status” light is yellow.
Temperatures stabilizing at
slightly more than 0.3
degrees from set point.
No action required. If temperatures are too far
from set point, Temperature Control Status will
alarm.
“Column Temps Stabilized
Status” light NEVER turns
green.
One of the temperature
zones—T1, T2, or T3—
on the column does not
regulate. Possible fuse
blown for that circuit.
Check appropriate fuse.
Temperature control
module failed.
Substitute in a known good temperature
controller from one of the other zones.
Thermoelectric
cooler
(TEC) element has failed
on column.
When both sides of the TEC element are at or
very near the same temperature, the resistance
measured across the unit will be low,
approximately 10 ohms. Since good TEC
elements can produce a voltage when there is
a temperature difference between the two
sides, this will cause the polarity of the
resistance reading to reverse.
1. If at all possible, make sure that the CCN
“OPC Communication”
light is yellow.
st
Status”
light
Monitor Issues
Monitor Issues
Problem
is
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Problem
“Column Temps Stabilized
Status” light turns green
occasionally but does not stay
green.
Possible Cause
One or more of the
Column
Temperature
zones—T1, T2, or T3—is
stabilizing at more than
0.3° from set point.
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instrument has not operated for the previous
few hours so that there are no temperature
differences between the sides of the TEC
elements.
2. Disconnect the in-line connector, located
near the rear of the CCN, just above the drain
bottle for the temperature zone that is not
functioning. There will be three connectors,
each one for the top (T1), middle (T2), and
bottom T3.
3. Using a standard digital volt meter (DVM),
measure the resistance across the pins going
to the temperature zone under test. Reverse
the leads and retake the temperature
measurement. If the resistance is nearly the
same with the polarity switched, the zone is
good. If the resistance stays the same with the
same polarity, the zone has a bad TEC
element. If no bad TEC element is found,
contact DMT for further information.
4. If a zone is found to have a bad TEC
element, use a DVM probe and measure the
resistance across each of the TEC elements.
The elements are labeled on the quick
connects as TEC1, TEC2, TEC3, and TEC4.
5. When the defective TEC element is
located, unplug the bad TEC. Plug in the good
TEC to the other, good TEC, leaving the bad
TEC unplugged.
6. Check the resistance of the TEC elements
measuring at the Molex connector (CON-0256)
to ensure that the string is good.
7. Reconnect the in-line connector.
8. Start the CCN instrument and run a
supersaturation scan to verify that the
temperature zone is controlling properly.
No customer-adjustable solutions. Contact DMT
for further help.
Note: If temperatures are being controlled but
stabilization point is only slightly more than .3
degrees from set point, (< .4), the unit is probably
functioning properly.
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Operator Manual, Cloud Condensation Nuclei Counter
Problem
Possible Cause
Major system failure, computer
not booting, all system values
reading
significantly
off,
negative
values
for
temperatures.
Power supply problem
Solutions
The power supply board and the CCN control
board have LED units for each of the power
supplies; see Figure 10. The supply voltage is
identified on the silkscreen near the LED and if
the LED is not lit, the problem is most likely in
the fuse or power supply. Table 2 lists the fuses
in the CCN, values and applications. The fuses
used are a printed circuit type, and it is not
possible to tell visually if they have failed. It is
necessary to check the fuses with some type of
continuity device.
Power Supply PCB
Fuse
Value
Application
F1
5A
12 DC-DC converter
F2
2A
F3
F4
F5
Control PCB
Fuse
Value
Application
OPC power
F2
6.3A
Top TEC controller
3.15A
Computer power
F3
6.3A
Middle TEC controller
2A
5V DC-DC Converter
F4
6.3A
Bottom TEC controller
3.15A
Touch screen power
F5
28 VDC spare circuit
F7
2A
Nafion heater
F8
2A
Inlet heater
F9
2A
OPC heater
Table 2: CCN Fuse Listing
Possible Cause
Solutions
System flow is zero with
pump operational
Cold trap for water
removal in line frozen, or
pump diaphragm failed
Shut off the CCN unit and wait 15 minutes.
Restart the unit, and if flow resumes, the cold
trap has most likely frozen. Please contact DMT
for instructions on adjusting the temperature on
this unit. If the flow does not resume, remove
lines from sample pump and check flow with
CCN system disconnected. If the pump does
not have substantial vacuum, most likely the
diaphragm has failed. Replace diaphragm or
pump.
Flow Issues
Problem
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Problem
Possible Cause
Flow ratio of 10.0 cannot be
achieved, and flow ratio is
less than 10.0 but stable.
Sheath flow
restriction.
filter
has
Unstable flow or flow noise.
Flow ratio unstable.
Water
droplets
have
caused a restriction in the
sheath flow line. Refer to
Figure 3.
Solutions
Replace sheath flow filter.
1. Shut Off CNN instrument.
2. Remove the Nafion drain plug.
3. Gently apply suction to the 1/4 X 28 drain
plug using a syringe or other suction device.
Note if any water is removed.
4. Reinstall the ¼ inch Nafion drain plug.
Unstable flow or flow noise
returns after removing water
droplets from the sheath line.
Nafion membrane tube
may have dried out and
shrunk or collapsed. Liner
shrinks approximately .75”
when it is dry.
Follow the membrane inspection procedure
outlined below. Replace or reseat the
membrane if necessary.
To inspect the membrane:
1.
2.
3.
4.
5.
6.
7.
8.
Remove the 1/8” compression nuts with tubing from the top and bottom “T”
on the Nafion block. The water will drain out when nut is removed. Have a
paper towel under it to catch water.
Unscrew tee fittings on the Nafion Block.
Inspect the top and bottom of the Nafion. The membrane liner should be held
in place with o-rings. The membrane should extend slightly out of the o-rings
and protrude above the fittings equally on top and bottom. If the membrane
has shrunk out of the o-ring on either end, this will allow water to flow
directly into the sheath line. Be careful not to let the Nafion membrane get
pushed inside the block on both ends, as one end needs to be exposed for
removal.
Remove the o-rings on the top and bottom.
Remove the membrane by sliding it from the top or bottom of the Nafion
block. Do not touch the membrane itself with your bare hands.
Inspect the membrane. It should be round and have no areas that are
deformed or collapsed. It will have a gentle curve to it. If the membrane looks
defective, it needs to be replaced (see Figure 24 and Figure 25).
Soak the membrane in distilled or deionized water for 10 minutes to allow it
to maximize its length.
Gently slide one end of Nafion membrane onto Nafion Insertion Tool (Figure
23).
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9.
10.
11.
12.
13.
14.
Insert tool into Nafion block and push through other end. There is a blind hole
at the bottom that the tool needs to find.
Adjust the Nafion membrane in Nafion block so that it extends equally out the
top and bottom.
Reinstall the o-rings on top and bottom around the membrane.
Screw tee fittings on back of the Nafion block.
Reinstall 1/8” nuts with tubing into tees.
Turn on supply pump to wet membrane.
If the problem persists, contact DMT.
Figure 23: Nafion Insertion
Figure 24: Typical Healthy Membrane
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Counting issues
Pump issues
Figure 25: Typical Bad Membrane. Note the kinks and flat spots.
Problem
Possible Cause
Solutions
Solenoid pump is “clicking” but
has no flow
Reeds in the pump have
adhered together
Ensure power is on and pump is energized.
Remove inlet and out fittings from solenoid
pump and gently blow some compressed air
into the INLET side of the pump to separate
reeds.
Sample pump turns off briefly
and back on
Temperature of OPC is
equal or lower than
bottom of column
temperature, T3.
This is normal operation, as the computer is
programmed to shut off the pump if the OPC
temperature is less than T3.
CCN is overcounting or
undercounting particles
Sheath filter is failing and
passing particles (Note:
this is only a possibility
if the CCN is overcounting)
Replace sheath filter. Refer to Appendix G for
more details.
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Pump issues
Problem
Possible Cause
Flows are incorrect
Check Sample and Total Flows.
Comparison set-up /
reference
instruments
are not balanced or set
up
properly—for
example, there is a
problem with the DMA.
Verify comparison setup by comparing a known
good unit to the suspect CCN. Contact DMT for
details.
OPC
isn’t
calibrated
Swap out suspect OPC with a known good
OPC. Contact DMT for details.
properly
CCN unit itself
properly calibrated
No particle counts appear
under
conditions
where
particles would be expected.
Counting issues
isn’t
Column is dried out.
OPC
windows
fogged.
With filter on inlet, unit still
counts particles at a rate of
more than 3 a minute.
Solutions
Return unit for factory calibration.
Check water supply, and check the solenoid
pump operation for column water feed. If the
column has dried out, it may take several hours to
wet the column.
are
There is the potential that the OPC window has
fogged due to a system upset. Click on the
OPC tab, and then look at the values displayed
in the Baseline Mon and 1st Stage Mon
windows. Standard operating values for these
parameters are provided in the setup sheets
with the instrument. The 1st Stage Mon is the
best diagnostic if the OPC has fogged. In
normal operation, this value will be .2-.3 V. If
the OPC has fogged, however, this value will be
up to 5 V. If the value drops from 5 V when the
OPC heater turns on, the fogging is minor and
will clear usually in 30 minutes or less. If the
OPC circulation pump is not at high speed, it
should be set to high speed (2 seconds) to
expedite clearing the OPC. If the OPC does not
clear in 12 hours, or you need to clear the OPC
more quickly, refer to Figure 22: Air Drying OPC
with Canned Air. Contact DMT for additional
instructions.
A very small amount of
ambient air is fed back
into the manifold; under
normal
operating
To achieve a zero count of less than 3 per
minute, the bottle vents going to the manifold
need to be removed and the manifold needs to
have plugs (PLUM-0185 provided in start-up kit)
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Problem
Possible Cause
Pump issues
conditions
this
unnoticeable.
Leak is suspected.
is
Solutions
installed.
Possible leak.
Leak test unit; see section 3.3.
Possible bad filter
Replace filter.
Leak in unit.
Perform the leak test described in section 3.3.
Warning
Do not stress flow sensors by releasing vacuum quickly or damage may occur.
Use a valve and open it slowly to get pressure back to ambient.
Do not leave unit unattended with plug on inlet and pump on; flooding of unit
could occur. Supervise leak test. If pressure needs to be applied to find leaks,
pressurize to no more than 5 PSI.
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PART II: THE CCN SOFTWARE
11.0 Product Description
11.1 Introduction
The computer system for the Cloud Condensation Nuclei Counter (CCN) is a PC-104 stack
unit with a Celeron 1 GHz processor, 500 Mb of memory, a Diamond Systems MM-16 AT
multifunction interface card, and a Sealevel 2-port communication card. A 16-Gb solidstate hard drive is provided for program and data storage. The operating system is
Windows XPEmbedded. Do not install any other programs, as conflicts may occur. Do not
set or change time either manually or with a time-sync program while the VI is running,
or the program will not operate properly.
Note: This computer configuration is accurate as of May 2009. Previous units and later
units may have different components as parts become obsolete or are upgraded.
The software for the CCN counter is provided as a LabVIEW executable. The software
revision level is shown in the status bar of the CCN counter program. This manual is
intended for versions 5.0.0 and above.iii Help screens are available while running the
instrument. They contain the most important information that is included in this manual.
Four programs are provided:
Single CCN.exe operates the CCN unit. This is the main program.
CCN SS Settings Config Editor.exe sets up the supersaturation
tables, which are stored in C:\CCN_SS_Settings.ini.
CCN Calibration Editor.exe sets the instrument-specific coefficients
for the flow and pressure calibrations. These are stored in
C:\CCN_Calibration.ini.
CCN Playback.exe displays and replays saved data files.
The following sections discuss the details of each of these programs.
In addition to these standard programs, DMT offers an optional Particle Analysis and
Display System (PADS) module for the CCN. This module allows integrated use of the CCN
with other DMT instruments.
iii
Screen shots in this document are taken from versions 5.0.3 (Single CNN.exe), 5.0.1 (SS
Settings Config Editor.vi and CCN Calibration Config Editor.vi), and 5.0.2 (Single CCN
Playback.exe).
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12.0 SINGLE CCN.exe (Main Program)
The Single CCN.exe control program provides a completely automated system for running
the CCN instrument under laboratory or flight conditions. The program loads and runs
automatically after the operating system boots. The display is organized into a tab
structure for control and monitoring of the system, as shown in Figure 26.
Figure 26: Main Screen of SINGLE CCN Program
In the upper right of the display are fields showing the date, time, and current data file
that the program is writing to. The Status button indicates the instrument status (green =
normal, yellow = an alert has been generated, red = an alarm has been generated). The
Status window displays any alarms or alerts concerning the operation of the software or
the instrument. During startup, the window shows the time available to select a
supersaturation table.
The main screen is divided into four sections. In the upper left are the control tabs.
Beneath the control tabs is a histogram display of particle counts by size. The histogram
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display is for the current moment in time. In the upper right of the screen is a chart of
particle number concentration with respect to time. Beneath this chart are additional
time-series charts as well as a Serial Output tab and DMT Service tab, labeled “DMT,”
which can be used during troubleshooting. The remainder of this section discusses these
various screen components in detail.
12.1 Control Tabs
12.1.1 SS Tab (Supersaturation Settings)
The control program will start with the supersaturation tab setting active (see Figure 27).
Figure 27: Supersaturation (SS) Settings Tab Display
12.1.1.1
SS Tab Settings that Must be Configured in First 10 Seconds
After starting the program, the user has 10 seconds to select the desired supersaturation
table from the SS Table pull-down menu. If no selection is made, the last SS table used is
selected by default. After the 10-second timer expires, the supersaturation values,
durations, and OPC bin settings are loaded and cannot be altered. Details on setting up
the supersaturation tables are given in section 13.0.
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During the first 10 seconds of program operation, the user can also select Dry Start Up or
Dry Shut Down. This can be done using the radio buttons shown in Figure 28. (These
buttons disappear from the display after the ten-second window has expired, as shown in
Figure 27.)
Figure 28: Dry Start Up and Dry Shut Down Buttons
Dry Start Up should only be selected when the unit has been totally dried out, such as
after shipping. Selecting Dry Start Up will set the liquid supply pump to high and disable
the CCN concentration alarm. After 4 – 12 hours, the unit will reset itself to normal
mode.
Dry Shut Down should only be selected when the unit needs to be totally dried out prior
to shipping. Selecting Dry Shut Down will prompt the user to shut the sheath flow
metering valve and install Drierite on the inlet. The supply pump will be turned off and
the drain pumps (i.e., the column and cold trap pumps) will be turned on high. The total
flow will be set to 175 Vccm. The CCN concentration status and flow status alarms will be
disabled. After 6 hours, the unit will turn off the TEC relay and display a message that
the unit is dried out and ready to ship.
12.1.1.2
SS Tab General Settings
Index displays the supersaturation level that appears in the top row of the SS%-Duration
table. In Figure 27, for instance, the top row has an index of 0, so this row corresponds to
the first entry in the supersaturation table. If you were to change Index to 1, the top row
would have an SS% value of 0.2 and a Duration of 3. Note that the top row is not
necessarily the CCN’s active supersaturation level—the instrument may have progressed
through this supersaturation and currently be operating on another level.
Current SS% displays the instrument’s current supersaturation, while Current SS#
displays the current supersaturation level in the SS Table. In Figure 27, the CCN is
currently operating on supersaturation level 2, which has a corresponding supersaturation
of 0.3%. Note that if the CCN is changing between supersaturations, the actual
supersaturation in the column may differ from the value displayed in Current SS% (see
section 12.1.2).
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# of SS displays the number of supersaturation levels in the current SS Table.
SS Table displays the currently selected SS Table. During the first 10 seconds of program
operation, this button is a control that can be used to select a table; after that, it is an
indicator that cannot be changed. Details on setting up the supersaturation tables are
given in section 13.0.
Seconds until SS change counts down the remaining time in seconds for the current
supersaturation selection. After the last selection completes, the instrument continues
and loops back to the 1st selection.
Note: Current SS# and Seconds until SS change are not visible when Manual SS mode is
turned on. See Figure 29.
Figure 29: Supersaturation (SS) Settings Tab Display in Manual SS Mode
The SS Control switch specifies how supersaturations are set. In Auto SS mode, the CCN
uses the SS Table to determine Current SS%. Delta T(C) is selected automatically based
on this SS% value. In Manual SS mode, the user enters either the supersaturation or Delta
T Set (C), which in turn determines the supersaturation. In Manual SS mode, the Manual
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Input Selection radio button (Figure 29, bottom middle) specifies whether the user will
enter Delta T Set (C) or enter the supersaturation directly. If the manual input selection
is Delta T Set (C), an SS indicator will appear above the Delta T set (C) control (bottom
right), which enables the user to quickly see what SS% the currently selected Delta T Set
(C) is equal to. The default value for Delta T Set (C) is the last setting the program was
previously running when Auto SS mode is switched off. Note that while the SS Table
remains visible during Manual SS mode, the program is not using it.
12.1.2 Temps Tab (Temperatures)
The Temps tab contains heater and temperature indicators and controls, as shown in
Figure 30. Note: To manually set the temperature gradient, Delta T Set (C), use the
SS Tab.
Figure 30: Temperature Tab Screen Showing Temperature Set Points and
Read-Outs the CCN Temperatures
The temperature designations are as follows:
T1
T2
T3
T OPC
T Inlet
T Nafion
Top of column temperature
Middle of column temperature
Bottom of column temperature
Optical Particle Counter temperature
Temperature of the particle inlet at the head of the column
Nafion humidifier temperature
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T Sample
Air sample temperature at the CCN manifold. (Note: Regardless of
the actual air temperature, T Sample will be close to ambient
temperature, as the air warms to ambient by the time it reaches
the manifold.)
“Set” refers to a given temperature’s set point, while “Read” refers to the observed
value. (The T inlet, T nafion and T OPC fields display observed values.)
The three indicator lights to the right of the Inlet Set, Nafion Set, and OPC Set fields are
for the Inlet heater, Nafion heater, and OPC heater, respectively. These lights are
illuminated when the respective heater is ON.
The four temperature differentials are read from the C:\CCN_SS_Settings.ini file at
startup and can be changed when the CCN is in Manual SS mode. Changes apply to the
current session only. To change the permanent default values for these differentials, do
so from the CNN Calibration Editor.exe program; see section 14.0.
T1 – Tsample is a temperature differential that determines the temperature of the top of
the column relative to the sample air temperature. TNafion – T1, Tinlet – T1, and TOPC
– T3 determine the temperature of the Nafion humidifier, the inlet manifold, and the
OPC relative to temperatures at points on the column. Recommended values for these
temperature differentials are given below.
(T1 – T Sample)
(T Nafion – T1)
(T Inlet – T1)
(T OPC – T3)
Recommended Value
2.0° C
-1.0° C
1.0° C
2.0° C
Range
0 °C to 10 °C
-5 °C to 5°C
0 °C to 5 °C
1 °C to 10 °C
The Column Temps Stabilized light indicates if T1, T2, and T3 are less than 0.4° from
their set values. Even when the light is on, additional time may be needed before the
entire unit is stabilized and data are consistent.
The light will turn off during SS% changes. For small SS% changes, the light will typically
be off for less than one minute. If the Column Temps Stabilized light never comes on,
refer to the Troubleshooting section.
TEC Relay switches the instrument’s 28 VDC power buss on and off. This supplies power
to the heaters, the TEC units, and the sample pump. The default value is on, but it can
be useful to turn off TEC Relay during troubleshooting.
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Delta T(C) is the temperature gradient used to calculate values for T1 Set, T2 Set, T3
Set, Inlet Set, Nafion Set, and OPC Set.
In Auto SS mode, Delta T(C) is an indicator only, where Delta T(C) is determined
by the Current SS% and the temperature gradient slope and intercept
coefficients. (See sections 12.4.2.2 and 14.0.)
In Manual SS mode, Delta T(C) becomes a control and can be set through the
Temps tab or through the serial port; see section 12.4.1.
12.1.2.1
CCN Temperature Adjustment
The program will readjust the temperature set values if any of these four following
conditions are met:
1.
2.
3.
4.
Delta T(C) changes
T Sample +2*(T1 - TSample) < T1 Set
T Sample > T1 Set
The unit has looped back to SS #1
Conditions 2 and 3 ensure that the temperature at the top of the column stays slightly
above the temperature of the sample. If the top of the column temperature is not above
the sample temperature, the air comes into the top of the column from the Nafion
humidifier, which is at 100% RH, can condense and cause fog to form at the top of the
column. Thus, if the sample temperature rises by more than the (T1 Set – TSample)
value, the system will reset all of the temperatures up to maintain this temperature
difference. If the sample temperature drops by twice the difference of the (T1 –
TSample) value, the T1 value will be reset lower.
It is also important that the operating temperature of the CCN be higher than the dew
point of the air being sampled. If the CCN is operated in a room with substantial air
conditioning, and the temperature of the air in the room is less than the dew point of the
sampled air, aerosol changes can occur.
When the CCN adjusts set temperatures, the new values are calculated using the
equations below.
T1 Set
new
= Sample Temp Setpointiv + (T1 – TSample)
iv
Sample Temp Setpoint is a temporary variable used by the software. It is equal to whatever
TSample was when conditions 2 or 3 were last true.
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T2 Set
new
= T1 Set
new
+ ½ Delta T(C)
T3 Set
new
= T1 Set
new
+ Delta T(C) * (1 – (%TGv)/100)
Nafion Set
Inlet Set
OPC Set
new
new
new
= T1 Set
new
= T1 Set
= T3 Set
new
new
+ (T Nafion – T1)
+ (T Inlet – T1)
+ (T OPC – T3)
In order to protect the laser diode in the OPC, if OPC Set
reduced using the following algorithm:
new
> 55 °C, then Delta T(C) is
1.) Delta T(C) new = 50 + Delta T(C) - OPC Set new
2.) All temperatures are readjusted using Delta T(C) new
3.) Steps 1 and 2 are repeated until OPC Set < 55°
It is important that the OPC operate at a higher temperature than the bottom of the
column, T3. This temperature differential ensures that the OPC optics will not fog.
Studies at DMT have shown that the OPC temperature can be as high as 5 °C above T3
with no loss of concentration. At an OPC temperature of 7 °C above T3, there is a 20%
loss of droplets.
If the supersaturation scans involve changing from a high supersaturation where the
OPC temperature is high to a low supersaturation and low OPC temperature,
adequate time must be allowed for the OPC to cool to 2°C above T3 before taking
data. Otherwise there will be undercounting of the activated particles.
12.1.3 Flows Tab
The Flows tab contains indicators and controls associated with the system flows, as
shown in Figure 31.
v
%TG is a temperature-gradient adjustment factor. For details, see section 14.0.
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Figure 31: Flows Control Tab
Flow Set (Vccm) displays the set value for the current total flow. This value is read from
the SS_Settings.ini file when the SS Table is selected, but can be changed at any time.
The recommended flow range is near 500 volume CC/min (Vccm), although the
instrument can process flows from 200-1000 Vccm.
Note:
Flow affects unit SS%. The CCN unit was DMT factory
calibrated with a Total Flow set to 500 Vccm, so Total
Flow should be approximately this amount.
Valve Set (V) displays the voltage sent to the proportional valve that regulates the total
airflow through the CCN. Every proportional valve will use a different Valve Set (V) to
maintain a given flow. Valve Set (V) is an indicator that cannot be changed.
Manual Override switches the manual valve set mode ON/OFF. In manual override mode,
the Valve Set (V) will be ignored and a constant voltage, Valve Set M (V), will be used in
its place.
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Valve Set M (V) controls the voltage supplied to the proportional control valve. This
parameter is only used when the instrument is in manual override mode.
Sample Flow (Vccm) displays the measured sample flow.
Sheath Flow (Vccm) displays the measured sheath flow.
Total Flow (Vccm) displays Sheath Flow (Vccm) + Sample Flow (Vccm). While the Total
Flow ranges from 200-1000 volume cc/min (Vccm), the instrument has been calibrated at
500 Vccm, and actual flow should be close to this amount to ensure data accuracy.
Flow Ratio displays Sheath Flow (Vccm) / Sample Flow (Vccm). A manually controlled
valve inside the instrument controls the split between the sample and sheath flows. The
recommended flow ratio is 10:1.
Liquid Supply Pump switches the supply pump ON/OFF. The two drain pumps run
continuously.
Sample Press (mb) displays sample pressure.
Air Pump switches the air pump ON/OFF. The default is ON. To prevent fogging of the
OPC, if T OPC < T3 Read the air pump switch will be overridden and the air pump will be
turned off. The user may also want to switch off the air pump during a leak test or when
drying the OPC with canned air.
Liquid Flow Set controls the frequency of the solenoid pumps used in the water supply
and drains. The pump frequency can be set to Low, Medium, or High.
Low is good for normal operation. This supplies sufficient water to the column for
ambient CCN measurement when the sample temperatures are below 33 °C.
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Medium is required for environments where the temperature is above 33 °C, or
the sample air to the CCN is dried with a diffusion drier. This supplies the extra
water used by the Nafion humidifier and the column at higher temperatures.
High is useful if water supply has run dry or if it is necessary to wet the column
quickly.
Liquid Supply Pump switches the supply pump ON/OFF. The two drain pumps—i.e., the
column and cold trap pumps—run continuously.
12.1.4 OPC Tab (Optical Particle Counter)
The OPC tab contains controls and indicators for the operation of the OPC. Figure 32
shows this tab.
Figure 32: Optical Particle Counter Tab
The OPC measures the sizes of particles at the exit of the column. The particles are sized
into 20 bins, with the bins’ upper boundaries at 0.75 µm, 1.0 µm, 1.5 µm, 2.0 µm, and
continuing in .5 µm increments until the last bin’s upper boundary of 10 µm.
The Bin Settings table displays the bin settings for each supersaturation setting. The bin
setting can be used to limit the Number Conc. calculation to reflect larger particles only.
Bins lower than the Bin Setting do not have their particles included in the concentration
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calculation. If all particles are to be included, Bin Setting should be 0, which is the
default value. Bin settings are loaded when the SS Table is selected and cannot be
changed. The program CCN SS Settings Config Editor.exe allows users to configure bin
settings for different supersaturation settings.
Index displays the number of the first bin setting displayed in the array. In Figure 32, for
instance, the first bin setting displayed corresponds to the first row (index 0) in the SS
Table.
Particle Size displays the particle size that corresponds to the top value listed in the Bin
Setting array.
Manual Control activates the slider bar that allows setting a manual Bin #.
CCN Number Conc. displays the number concentration using the counts from particle
bins above the Particle Size and any overflow counts.
Overflow displays the number of particles counted that are larger than 10 µm.
Baseline Mon displays a voltage used by DMT for OPC diagnostic purposes.
Laser Curr displays the laser current (mA) used in the OPC. A sudden change in current
could reflect a problem with the instrument. A reading of 60 – 120 mA indicates the
instrument is functioning properly. See Appendix A for more details.
1st Stage Mon indicates whether the OPC is fogged. The normal operating range for this
voltage is 0.1 - 0.75 volts. If the OPC is fogged, this voltage may be as high as 5 volts. If
this happens, turn up the temperature on the OPC to 5° above T3. This can be done by
clicking on the Temps tab, switching to Manual SS mode, and changing the TOPC – T3
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temperature differential. Next, watch for a drop in the 1st Stage Mon level. If the value
drops as the OPC heater cycles on, it is an indication that the OPC is not heavily fogged
and it usually will recover in an hour or two. To speed the drying of the OPC, turn the
cycling of the OPC drying pump to the 2-second setting. This switch is labeled SW1 and is
located in the middle of the Controller Printed Circuit Board; see Figure 10. After the
OPC is dry, the switch should be reset in the 16-second position.
Laser current alarm level displays the level at which an alert will be given when the
laser draws this amount or more of current. Such an alert indicates the laser is nearing
the end of its life.
12.1.5 Monitor Tab (Alarm Monitoring)
The Monitor tab has indicators for monitoring and logging the status of systems. Figure 33
shows this tab. When buttons are lit, as in Figure 33, the instrument is functioning
properly.
Figure 33: Monitor Tab
The status of the instrument is categorized as Normal, Alert, or Alarm. Normal indicates
no alerts or alarms are present. Alert is triggered by a possible problem and takes no
actions in the instrument. An alert is indicated by a yellow monitor button. Alarm is
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triggered by a probable problem and will put the CCN in safe mode. Safe mode shuts off
the TEC relay and Liquid Supply Pump. The relevant monitor button will turn red.
The timers in the status fields count how long the specified alert/alarm conditions have
been met. They are reset to 00:00 if the conditions are not met, i.e. if no problem has
been detected. If any timer exceeds its set threshold, an alert/alarm is triggered and the
indicator light turns yellow for an alert and red for an alarm. Each alert is associated
with a unique alert code. Alert codes are integers in the form of 2 n, where n = 0, 1, 2 …
14. The sum of all triggered alerts is saved in the last column of the data file. This sum is
then made negative if any alarms have been triggered.
More information is given below about specific status fields, their corresponding alert
codes, and whether the system ultimately generates an alarm for this problem.
12.1.5.1
CCN Alerts and Alarms
Laser Current Status alerts if the laser draws too much current, indicating the laser
diode is nearing the end of its useful life. Contact DMT. No alarm. Alert Code = 1.
OPC Communication alerts if the OPC is not communicating with the computer. No
alarm. Alert Code = 256.
1st Stage Monitor Voltage Status counts when the 1st Stage monitor is > 4.7 V. Alerts
after 5 minutes. No alarm. Alert Code = 2.
Flow Status counts when total flow deviates >20% from the set flow or when the flow
ratio is not within 5-15. Alerts after 30 minutes. No alarm. Alert Code = 4.
Temp Control Status counts when at least one of T1, T2, T3, T Inlet, T Nafion, and T
OPC is more than 10 degrees from its set point. Alerts after 10 minutes. Alarms after 20
minutes. Alert Code = 8.
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Sample Temp Status counts when the sample temperature exceeds the 0-50 °C range.
Alerts after 1 minute. Alarms after 5 minutes. Alert Code = 16.
OPC Status counts when the 1st Stage Monitor > 4.7 V and CCN counts are less than the
configured threshold. DMT sets this threshold to the factory default of 10 counts/sec, but
it can be changed by the user using the CCN Calibration Editor.exe program. No Alert.
Alarms after 60 minutes. Alert Code = 32.
CCN Concentration Status counts when CCN counts are less than the configured
threshold (factory default 10 counts/sec). Alerts after 20 minutes. Alarms after 120
minutes. Alert Code = 64.
Column Temps Stabilized Status counts when T1, T2, or T3 is >0.4 degrees from its set
point. Alerts after 20 minutes. No alarm. Alert Code = 128.
Duplicate File Name Status alerts when a file already exists with the same name as the
file that the CCN program wants to create. A new file will be created, which will have
the same name as the original file but have “duplicate.xxx” appended to it. Check and
fix, if necessary, the system clock. No alarm. Alert Code = 512.
Safe Mode flashes when an alarm has been triggered and the unit is in safe mode.
Reset Status clears all alerts/alarms and resets their timers to zero. This button will not
turn the TEC relays back on. It does turn the liquid supply pump back on.
12.1.5.2
How to Interpret CCN Alarm Codes in Output Files
When the CCN is running, any alerts and alarms will be displayed individually in the
Status window at the top of the main program screen. In the .csv and serial stream
output, however, alerts and alarms are stored as a sum of all the alarm codes generated.
For instance, say the CCN is generating an alarm code of 183. 183 = 128 + 64 + 1, which
means that alerts have been generated for Column Temp Stabilized, CCN Concentration
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and Laser Current Status. (Because the alarm code for each individual problem is a
unique 2n number, the sum of alarm codes will always indicate a unique set of issues.) A
negative alarm code indicates problems severe enough that the instrument has gone into
safe mode.
12.1.6 Chart Tab
The Chart tab, shown in Figure 34, contains controls for configuring the Flows,
Temperature, and CCN charts.
Figure 34: Chart Tab
Chart History Length controls the how far back the charts extend. The white slider on
the blue background selects the history length, which has a default value of four hours.
The green indicator shows the length of data available. Figure 34 shows the Chart tab
before a session has started. No data is available yet, but the chart display is set to show
up to four hours of data once it becomes available.
Show Legends controls the display of chart legends on top of the chart. If Show Legends
is enabled, charts will show legend boxes such as those depicted in Figure 34.
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12.1.7 Prog Tab (Program Control)
The Program Control tab contains controls for file saving and data streaming, as shown in
Figure 35.
Figure 35: Program Control Tab
Saving File controls whether the data is saved or discarded. This button is on by default.
(See section 12.6 for information on file names and content.)
Start New File forces a new file to be started.
Start New File Every x min controls the length of data files. The default value is 60
minutes, and the allowed range is 1-180 minutes. The setting options work as follows. 1
hour, 2 hours, and 3 hours start the first file at when data recording begins and the
remaining files on the hour. For instance, if you set Start New File Every x min to 2
hours and start sampling at 7:56 a.m., the first file will begin at 7:56, the next at 9:00,
and the next at 11:00. If you select User Defined and specify the number of minutes in
the minutes pop-up field, however, files will not start on the hour. So, if you set Start
New File Every x min to User Defined and set minutes to 120, files will begin at 7:56,
9:56, 11:56 and so on.
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Shutdown stops the execution of the program and closes the files properly. This button
should be used whenever exiting the program.
WARNING:
It is important to use the Shutdown button when shutting down the instrument; this will
ensure that the pumps are shut off in order and the files are saved properly.
Watch dog alternates ON and OFF every second when the computer is cycling properly.
The watch dog light on the instrument should blink at the same time as the indicator on
the computer screen. (The watch dog light is located on the side of the CCN; see Figure
9.) If the indicator light is steady OFF or ON, reboot the computer.
12.2 Histogram
Beneath the Control Tabs is the histogram of raw particle counts by size, as shown in
Figure 36.
Figure 36: Histogram
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For information on configuring the histogram display, see section 16.0.
12.3 Particle Concentration Time-Series Chart
In the upper right of the main CCN screen is the particle concentration chart, as shown in
Figure 37.
Figure 37: Time-Series Concentration Chart
For information on configuring the chart display, see section 16.0.
12.4 Other Time-Series Charts and DMT Service Tab
In the bottom right of the main Single CCN screen are the flow time-series chart, the
temperature time-series chart, and the DMT Service Tab.
The Flow Chart plots Sample Flow, Sheath, Flow and Total Flow with respect to
time.
The Temperature Chart plots the temperatures of various CCN components over
time. See section 12.1.2 for details and the normal range for these temperatures.
The Temperature Chart also indicates the temperature of the sample air.
The Serial Output Tab is described below.
The DMT Service Tab is described below.
12.4.1 Serial Output Tab
Users have three options for how the CCN handles serial output:
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The instrument generates no serial output.
The instrument generates a standard stream of serial output. Note: This option
must be used to interface with PADS.
The instrument generates a user-configured stream of serial output.
These options are described in more detail below. The radio buttons in the upper left of
the Serial Output tab (Figure 38) allow users to select the option they prefer.
Figure 38: Serial Output Tab
If serial output is set to None, the white columns above will disappear from the Serial
Output tab.
If serial output is set to Normal, the CCN will output two lines (Line H and Line C) of
serial stream data. In this case, the columns displayed in the Serial Output tab are for
informational purposes only; users cannot manipulate the display to configure the serial
stream. The first serial stream will always start with a time stamp, followed by an “H,”
followed by the output channels displayed in the left column of Figure 38. (For a list of
these channels, see section 12.6.1.) A carriage return separates the first set of data from
the second, which starts with a “C” and continues with the output channels specified in
the column on the right in Figure 38.
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If serial output is set to User Defined, users can select the desired output channels from
a list of all available channels. To include channels in the serial stream, select the
channels by clicking on them. Holding down the <Shift> and <Control> keys allows you to
select multiple channels at once. Note that the order of channels must follow that in the
list of all available channels.
12.4.2 DMT Service Tab
Figure 39: DMT Service Tab
The DMT tab is used to access the CCN service tabs. These tabs are hidden and locked
during normal operation. They can be accessed by clicking the text window in the middle
of the screen and typing the password Service. When the password is entered correctly,
tabs for PID, Gains, Flow and Error/Exit will appear (Figure 40). These tabs can be used
to update the calibration parameters in real time, without having to restart the program.
(In contrast, changes made to these same parameters using the CCN Calibration
Editor.exe program require restarting Single CCN.exe before the updates will take
effect.) The new values can be saved as defaults by pressing the Save button. If the Save
button is not pressed, any values entered will only apply to the current session.
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12.4.2.1
DMT Service Tab: PID Section
The PID screen, pictured in Figure 40, allows users to modify the CCN’s proportional valve
flow control loop. Specifically, the parameters on this tab determine how the CCN’s
proportional valve voltage will shift from its current state to a higher or lower one.vi During
any such transition, the optimal change is one that is 1.) quick, 2.) smooth, and 3.) does not
overshoot its target—i.e., does not raise or lower the voltage too far. The challenge, however,
is that these three factors cannot be simultaneously optimized, as a very quick transition
typically overshoots its target.
Figure 40: DMT Service Tab – PID Section
The proportional valve is controlled by a PID loop. P (Proportional), I (Integral), and D
(Derivative) are variables used to control the valve’s voltage transition. P determines the
scale of the transition, and is akin to the multiplier that is used to get from the old voltage to
the new voltage. I the speed of the response time, with a higher I yielding a faster transition.
D determines how smooth the transition curve will be.
The default values that appear in the P, I, and D fields on the PID tab are adequate for
stable flow control in most cases. However, under certain circumstances, it may be
necessary to tune the PID loop for better control.
vi
The proportional valve voltage determines how open or closed the proportional valve will be,
which in turn regulates total sample flow.
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Max and Min value refer to the proportional valve voltage window the PID loop can
control. Each proportional valve has an operating range of about 1 V, but turn-on
voltages between valves can vary from 1.25 - 3.5 V. Thus one proportional valve may
operate at 1.25 – 2.25 V, while another operates at 2.5 – 3.5 V. Setting Min and Max
values so they create a wide window (0.1 – 4.9 V) accommodates all proportional valves.
Narrowing this window does not typically improve flow performance.
12.4.2.2
DMT Service Tab: Gains Section
Figure 41: DMT Service Tab – Gains Section
This tab allows users to enter the slope and intercept of the equation to convert SS% to
Temperature Gradient. Refer to section 8.1 for the complete SS% calibration procedure.
12.4.2.3
DMT Service Tab: FlowCal Section
The FlowCal tab is shown in Figure 42.
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Figure 42: DMT Service Tab – FlowCal Section
This tab allows users to enter the slopes and intercepts of the equations to convert voltage to
flow. To have the voltage of the transducer displayed in the CCN Flows tab, enter a slope of 1
and an intercept of 0. Refer to section 8.2 for the complete flow calibration procedure.
The Supply Pump and Drain Pump indicators blink during normal operation when the pumps
are on.
12.4.2.4
DMT Service Tab Error / Exit
The Error/Exit tab is shown in Figure 43. Its windows and information can be helpful when
troubleshooting with DMT’s help, but they should not be modified without assistance.
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Figure 43: DMT Service Tab – Error/Exit Section
Press exit on this tab to exit the DMT Service tab and end service mode. Although the unit
will function normally when in the service mode, it is recommended that users exit once
service is completed to avoid accidental input. The service mode is also exited upon closing of
the VI or rebooting the computer.
12.5 Program Input Files
The Single CCN.exe program requires two input files: CCN_SS_Settings.ini and
CCN_Calibration.ini. The former stores the supersaturation settings for the
instrument, while the latter stores instrument calibration and configuration information.
Both of these files are in the C:\ directory, but they should not be modified directly.
Instead, use the program CCN SS Settings Config Editor.exe to modify
CCN_SS_Settings.ini
and
CCN
Calibration
Editor.exe
to
modify
CCN_Calibration.ini.
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12.6 Program Output Data
12.6.1 Serial Stream
A serial output stream of data is available for sending to a host computer or other device.
A serial null modem cable must be used and is provided with the startup kit. The control
for this is the Serial Output button found on the Program Control tab (section 12.1.7).
The data appears on the DB-9 connector labeled “Data Out” and uses a RS-232
configuration with 9600 baud transmission and 8-N-1 data protocol. Connecting this port
to another computer requires the use of a null modem between the computers so that
pins 2 and 3 are swapped.
Users can select three options for serial stream output: no output, normal output, or
user-defined output. See section 12.4.1 for details. The list of available serial stream
output channels appears below. The two lines of data are separated by a carriage return.
The “H” and “C” that begin the columns are simply the characters H and C (i.e., these
are not the names of data channels).
First Data Line
H
Time
SS setting
Temp Stable ?
T1 read
T2 read
T3 read
Sample Temp
T inlet
T OPC
T Nafion
Sample flow
Sheath flow
Abs Press
Laser current
ST
1 Stage Monitor voltage
Temperature Gradient
Proportional Valve Voltage
Alarm Code
vii
Second Data Line
C
Bin setting
CCN Number Conc.
ADC overflow
Bin 1vii
Bin 2
Bin 3
Bin 4
Bin 5
Bin 6
Bin 7
Bin 8
Bin 9
Bin 10
Bin 11
Bin 12
Bin 13
Bin 14
Bin 15
Bin 16
Bin 17
Bin 18
Bin 19
Bin 20
All bin channels store are raw particle counts rather than concentrations.
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For definitions of these channels, see the Glossary in Appendix A.
Note: The user can also change the temperature gradient via the serial port (labeled
DATA OUT) when the AUTO SS button is off. To change the value, five characters must
be entered (example: 10.00, or 10.0 and a carriage return). To see what SS the
temperature gradient equals, press the SS tab and look in the lower right-hand corner for
the display labeled SS.
12.6.2 Output Files
The CCN instrument provides on-board file storage that can be retrieved by Remote
Desktop or over an Internet connection.
The frequency at which the program starts a new file can be set on the Program tab. Use
the New File Every (min) control depicted in Figure 35. If the setting for this parameter
is 20, the program will save a new file every 20 minutes using the file convention
described below.
The files are named “CCN data yyMMddhhmmss.csv” and are created in the C:\CCN
data directory. Note that the CCN data directory is not automatically created by the
software and must be created to store the data. The format of yyMMddhhmmss is as
follows:
yy = the two digits for year
MM = the two digits for month
dd = the two digits for day
hh = the two digits for hours
mm = the two digits for minutes
ss = the two digits for seconds
Example: May 6, 2004 at 4:18:27 would be 040506041827. This convention lists files
created sequentially from start time, which provides an easy way to locate specific files.
Output files contain the following data channels:
Time
SS Setting
TempStab?
Delta T Set
T1 Set
T1 Read
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Sample flow
Sheath flow
Abs. Press
Laser Current (mA)
ADC overflow
Bin 8
Bin 9
Bin 10
Bin 11
Bin 12
Bin 13
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T2 Set
T2 Read
T3 Set
T3 Read
Nafion Set
T Nafion
Inlet Set
T Inlet
OPC set
T OPC
Baseline Monitor
1st Stage Monitor
Bin Setting
Bin 1
Bin 2
Bin 3
Bin 4
Bin 5
Bin 6
Bin 7
Bin 14
Bin 15
Bin 16
Bin 17
Bin 18
Bin 19
Bin 20
Number Conc.
Alarm Code
As with serial-stream data, all Bin channels store raw particle counts rather than
concentration. For definitions of these channels, see the Glossary in Appendix A.
13.0 CCN SS Settings Config Editor.exe
The program CCN SS Settings Config Editor.exe allows the user to create up to four
predefined tables for operating the CCN in a scanning mode with variable supersaturation
and time periods. (Users can also enter manual values for SS% and Delta T Set (C); see
section 12.1.1.2). Figure 44 shows the configuration editor program.
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Figure 44: Program for Setting the Supersaturation Tables
When configuring supersaturation tables, it is recommended that the states progress from
lower supersaturations to higher ones. The CCN instrument performs best with gradual
increases in column temperature followed by a major cooling back to a low
supersaturation.
Tables 1 through 4 allow preconfigured settings to be loaded into the operating program.
These settings include the supersaturation rate, duration for the supersaturation setting,
the bin settings to be used in the CCN concentration calculations, and the set total flow.
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Once the table has been configured, click on Save to save this table, and move on to the
next desired configuration. The tab provides the option of four different supersaturation
tables. The fields at the bottom of the screen can be used to copy values from one table
to another in the event that two tables share a portion of data. Following the
configuration of all the desired tables, exit the CCN SS Settings Config Editor program.
14.0 CCN Calibration Editor.exe
The CCN Calibration Editor.exe program allows users to set calibration coefficients that
determine equations for flows, temperature gradient, proportional valve settings and so
on. The calibration coefficients for each of these measurements are stored in a table that
is accessed by the program. These systems are calibrated before the unit leaves DMT, but
it will be necessary to recalibrate them periodically. The USB memory stick that
accompanied the CCN upon delivery contains spreadsheets that are useful during
calibration.
Note that many of the calibration coefficients displayed in CCN Calibration Editor.exe
can also be modified by using the DMT Service tab on the control program, Single
CCN.exe. The control program only saves these changes if the Save button is pressed. In
contrast, the calibration editor program always saves changes and the new values will be
used upon startup of the control program.
14.1 Standard Screen
Opening CCN Calibration Editor.exe brings up the screen shown in Figure 45.
The left-hand column contains several controls for altering pressure coefficients. The
flow measurements on the CCN for the sample and sheaths flows use a differential
pressure transducer for each flow. In addition, an absolute pressure transducer is used
for the sample pressure measurement. To calibrate the transducers, set the slope value
to 1 for each of these parameters and the intercept to 0. In this way the values on the
Flows tab will read out in volts. A new set of calibration coefficients can then be derived
and entered into the program.
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Figure 45: CCN Calibration Editor.exe
Temp Gradient Slope and Intercept calibrate the proper temperature gradient to
achieve the desired supersaturation. Users who want to calibrate the CCN unit must
contact DMT prior to making any adjustment.
Valve Set Min sets the lower limit of Proportional Valve Control Voltage. By default, this
value is set to 0.1. It can be changed here or in the PID tab; see section 12.4.2.1.
Valve Set Max sets the upper limit of Proportional Valve Control Voltage. By default, this
value is set to 4.9. It can be changed here or in the PID tab; see section 12.4.2.1.
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T1 – Tsample is a temperature differential that determines the temperature of the top
of the column relative to the sample air temperature. TNafion – T1, Tinlet – T1, and
TOPC – T3 determine the temperature of the Nafion humidifier, the inlet manifold, and
the OPC relative to temperatures at points on the column. These differentials are in
degrees Celsius. Under normal operations these differentials should not be changed, but
increasing TOPC – T3 can prevent fogging of the OPC.
Alarm Threshold (low cts) sets the threshold value for CCN Number Conc. Alert (see
section 12.1.5). DMT sets this value to 10 counts per second, which is the factory default.
Monitor Alarm turns the monitoring feature on/off. Turning off monitoring disables the
alarms and the Monitor tab. Monitor Alarm should always be ON.
Single Line allows users to specify whether serial stream data should be in a single line
(no carriage return between data) or in a double line (a carriage return separating lines).
See section 12.6.1 for details.
14.2 Screen with DMT Settings
Additional parameters can be viewed by clicking on the Show DMT Settings button, which
is visible in the upper left of the screen. Pressing this button brings up the window shown
on the right-hand side of Figure 46.
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Figure 46: CCN Calibration Editor.exe with DMT Tabs
As noted on the screen itself, these settings should not be altered without contacting
DMT first.
T1, T2, and T3 Offsets and T1, T2, and T3 Gains adjust the read points of T1, T2, and
T3. These should never be adjusted by the user.
%TG enhances the response time between SS% changes. It causes the bottom
temperature zone of the column to run a certain percentage lower temperature than a
linear gradient. For example, if this percentage is set to 5% and there is a 10°
temperature gradient, the bottom temperature zone of the column will be set at 9.5°
(not 10°) hotter than the top temperature zone.
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NOTE: the desired temperature gradient will still be displayed in the delta T box.
But the actual set point of T3 will be offset lower by the %TG temperature gradient
percentage. The %TG parameter should never be adjusted by the user.
Max Laser Curr indicates the alarm threshold for the laser current. If the actual current
exceeds the value entered in this field, the CCN will generate an alarm.
Auto SS, Last Delta T, Delta SS, and TG Dum are parameters accessed by the CCN
software. They should never be changed.
The Sealevel Card Installed indicator is illuminated whenever the Sealevel card is
present. This indicator should be ON if your computer has this card. (Some older
computers have four COM ports on board, and so this additional COM port is not needed.)
If the Sealevel Card Installed indicator does not match the actual instrument
configuration, the serial stream may have an incorrect baud rate.
Liquid Supply Pump indicates whether the CCN’s supply pump has a 20 or 60 µl
displacement capacity per cycle. It is set to match the specifications of the pump, and
should not be changed unless a new pump is installed.
P, I, D, and Flow Avg # are used in the PID control loop. Flow Avg # is used in smoothing
the PID function. For information on P, I, and D, see section 12.4.2.1.
15.0 CCN Playback.exe
The CCN Playback.exe program allows you to play back data files that the CCN created
during an earlier session. The program display (Figure 47) is similar to that when the
Single CCN program is running. The display includes the following:
Tabular data on temperatures, flows, the OPC counter, and alarms
A histogram displaying particle counts by particle size
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Time-series charts for
concentration on topviii
particle
concentration
and
flows,
with
particle
There are also several differences between the displays in Single CCN.exe and CCN
Playback.exe. The latter does not feature Serial Output or DMT Service tabs. It does
include a Selectable Chart tab behind the histogram, which is described in section 15.2.
Figure 47: CCN Data Playback
The Read a File button in the top right opens a file explorer for selecting the data file to
be read. The program then displays this file path in a window at the top of a screen. The
currently displayed time is displayed on the Program Tab, and is indicated by a red
cursor in time-series charts.
15.1 Changing the Current Time
Once a file is loaded, there are two options for displaying data. To move forward in time
automatically, press the Playback button in the upper right of the window. The current
time will advance forward automatically, and updated data will populate the display. The
viii
Note: The software currently mislabels the y-axis for the particle concentration chart. Units
should be in particles/cc, not ccm. This bug will be fixed in an upcoming version of the program.
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speed can be changed using the Playback Speed dial on the Program tab, visible in
Figure 47 above.
Users can also change the current time manually using the timing controls on the left side
of the screen. Figure 48 shows these controls in more detail.
Figure 48: Playback Timing Controls
The arrow buttons can be used to advance or go back in time. The white controls that
show the start and end of displayed data can also be used for zooming in on the data. To
do this, move the two controls closer to each other, as shown in Figure 49.
Figure 49: Using Playback Controls for Zooming
15.2 Selectable Chart Options
Behind the Particle Counter is the Selectable Chart Tab. This tab, shown in Figure 50,
selects channels to display in the bottom chart on the right side of the window. The
default channels are the temperature values charted with respect to time.
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Figure 50: Selectable Chart Tab
16.0 Chart Options (for Single CCN and CCN
Playback Programs)
In both the Single CCN.exe and CCN Playback.exe programs, you can right-click on
charts such as the histogram and time-series charts to bring up additional options.
On many charts, you can change the scale by typing a different number into the starting
and ending values on each axis. For instance, if you want to change the time period in
one of the graphs above to end at an earlier time, you simply select the field with the old
time, type in the new time, and hit the <Enter> key. In acquisition mode, you must
disable autoscaling (see below) before you modify fields in this way.
Many charts also display options for scaling and copying the data when you right-click on
them, which brings up a drop-down menu. These options are as follows:
Autoscale This autoscales the relevant axis. In autoscaling mode, the minimum
and maximum values of the axis are set automatically so that all data points can
be seen in the display.
Copy Data This copies the chart to the clipboard using a screen capture. This
chart can then be pasted into other documents like Word or PowerPoint
presentations.
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Export Simplified Image This copies a simplified image of the data to the
clipboard or an output file. You can choose the format you desire—bitmap (.bmp),
encapsulated postscript (.eps), or enhanced metafile (.emf). Note that when you
select the .eps option, you must copy the data to a file. Unless you specify
otherwise, output files will be saved in the time-and-date-specific output file
directory for the current session.
Clear Graph This erases the currently displayed data points from the graph.
17.0 Remote Operation of CCN Programs through
a Network Connection (Remote Desktop)
The CCN instrument can be connected to using the instrument’s Ethernet port, which is
located with the other interface connections. The instrument can be connected to an
Intranet or to a single computer with a network crossover cable.
Remote Desktop is a program that can be run on a host machine that will connect to the
CCN instrument over the Internet. Remote Desktop is available online and must first be
installed on the host machine. In order to connect to the CCN instrument, run Remote
Desktop from the host machine. In the computer selection type CCNStack or the IP
address of the CCN instrument, then click Connect. The user should be administrator,
and the password for the CCN computer is password.
Once Remote Desktop connects to the instrument, you will have complete access to the
active desktop on the CCN computer from the host machine. All CCN programs will then
be accessible from the host machine. Files can be transferred from the CCN onboard
computer to the host machine using the right click copy and paste features. To transfer
files, navigate to the CCN data folder. Select the files to transfer, and copy them by
right-clicking and selecting Copy. Then minimize the remote desktop function, navigate
to the desired file location, and paste the files using the right-click function. After rightclicking to paste the files, it may take up to a minute for the program to respond.
Another option for copying files is to put them on a shared folder. You can share a folder
on the remote machine by double-clicking on it and then selecting Share This Folder
under the File and Folder tasks. This will bring up a window where you can select Share
This Folder using a radio button. After clicking OK, navigate back to the host machine
desktop. Bring up Windows Explorer and in the path field type “\\” followed by the IP
address of the remote desktop computer. The shared folder should now be visible, and
you can copy its files to any other location.
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Virtual Network Computing (VNC) is not supported by this version of windows XP at this
time. It is the responsibility of the user to set up the Remote Desktop of the CCN.
The following book is recommended for users needing assistance with networking to the
CCN: Microsoft Windows XP Networking Inside Out by Curt Simmons, published by
Microsoft Press.
The CCN computer name is “CCNStack” and the password is “password”.
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Appendix A: Glossary
%TG: A temperature-gradient adjustment factor that enhances the response time
between SS% changes. %TG causes the bottom temperature zone of the column to run a
certain percentage lower temperature than a linear gradient. For example, if this
percentage is set to 5% and there is a 10° temperature gradient, the bottom temperature
zone of the column will be set at 9.5° (not 10°) hotter than the top temperature zone.
Typically this number will be set to 7%.
1st Stage Monitor (V): A monitor that indicates whether the optical particle counter
(OPC) is fogged or dirty. When 1st Stage Mon exceeds its threshold for a sustained period,
the CCN computer generates an Alarm Code.
Abs Press: The absolute pressure in the CCN column. The absolute pressure is one factor
that determines the instrument’s supersaturation.
ADC Overflow: The number of particles that have been detected but rejected for
counting because they were oversized. Oversized particles send out a peak digital signal
that exceeds that given in a threshold table as the upper boundary of the uppermost
sizing bin. These particles are included in Number Conc.
Alarm Code: The sum of any current alarm codes the CCN computer has generated. Each
alarm code is a unique 2n number that reflects a specific issue with the CCN. For
instance, an alarm code of 4 indicates a problem with the total flow or with the samplesheath flow ratio. An alarm code of 16 indicates a problem with the sample temperature.
Problems with both the flow and the sample temperature would result in an Alarm Code
value of 20 (= 4 + 16), providing no other alarm codes have been generated. A negative
alarm code indicates problems severe enough that the instrument has gone into safe
mode. See section 12.1.5.2 for more details.
Baseline Monitor: A voltage indicator used by DMT for diagnosing the OPC. A healthy
reading is 2.5 – 3.2 V.
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Bin [i]: The raw particle count in bin number i.
Bin Setting: A parameter that can be used to limit the Number Conc calculation to
reflect larger particles only. Bins lower than the Bin Setting do not have their particles
included in this calculation. If all particles are to be included, Bin Setting should be 0.
The program CCN SS Settings Config Editor.exe allows users to configure bin settings for
different supersaturation settings. Bin Setting is also a channel in the output data.
Chiller: Another name for the CCN’s cold trap.
Cold trap: A device that condenses water out of the OPC exhaust, ensuring that water
does not condense in the instrument’s proportional valve or pump. See section 2.2.1 for
details.
Column Temps Stabilized Status: An indicator on the Monitor tab that corresponds to
the Temp Stable? output channel. This monitor triggers when T1 Read, T2 Read, or T3
Read is > 0.4 °C from its set point.
Current SS#: The level of the CCN’s current supersaturation. In Auto SS mode, the CCN
determines the sequence of supersaturations for the session using a supersaturation
table. All supersaturation tables start at level 0. Users can enter up to 256 different
supersaturations per table, so the maximum level is 255.
Current SS%: The CCN’s current supersaturation. Note that if the instrument is changing
supersaturations, Current SS% will differ from Current SS#.
Delta T Set (C): The temperature differential used to calculate values for T1 Set, T2 Set,
T3 Set, Inlet Set, Nafion Set, and OPC Set. Delta T Set (C) is equal to T3 Set – T1 Set.
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DMA: A differential mobility analyzer. DMAs are traditional devices for sizing aerosol
particles.
Dry Start Up: An option that can be selected during the first ten seconds of the CCN. Dry
Start Up should only be selected when the unit has been totally dried out, such as after
shipping.
Dry Shut Down: An option that can be selected during the first ten seconds of the CCN.
Dry Shut Down should only be selected when the unit needs to be totally dried out prior
to shipping.
Inlet Set (C): The set point temperature at the CCN inlet manifold.
Köhler Curve: A mathematical function representing the cloud-droplet formation
process. Köhler curves are used to calibrate the CCN and determine the relationship
between temperature gradient and supersaturation.
Laminar Flow: A flow in which the separate layers of air or fluid flow in parallel rather
than mixing together. The CCN uses a laminar flow element.
Laser Current (mA): The electrical current flowing through the instrument’s laser diode.
A sudden change in current could reflect a problem with the instrument. A reading of 60 –
120 mA indicates the instrument is functioning properly. A high laser current can indicate
the laser is nearing the end of its life. A sustained high Laser Current will generate an
Alarm Code.
Nafion Set (C): The set temperature of the Nafion humidifier. When this temperature
differs substantially from its set point for a sustained period, the CCN computer
generates an Alarm Code.
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Number Conc. / CCN Number Conc. (#/cm 3): The particle number concentration in
sized particles per cubic centimeter of air. This is calculated as follows:
Number Conc = [(Sum of qualifying Bin Counts) + (ADC Overflow)] / Sample Flow
60
The 60 is a unit conversion factor, since Bin Counts and ADC Overflow are given in
particles per second while Sample flow is in cm3/min. The CCN’s Number Conc. includes
oversized particles but does not include particles in bins smaller than the Bin Setting.
When Number Conc. falls below its threshold for a sustained period, the CCN computer
generates an Alarm Code.
OPC: An optical particle counter. The OPC component of the CCN counts and bins
activated aerosol particles in the sample air after they have grown to detectible size.
OPC Set (C): The set point temperature of the optical particle counter. When OPC Temp
(C) differs substantially from this set point for a sustained period, the CCN computer
generates an Alarm Code.
PADS: See Particle Analysis and Display System.
Particle Analysis and Display System (PADS): Optional DMT software that can be
purchased with the CCN. Like the CCN’s standard software, PADS is written in LabVIEW.
PADS provides data analysis and reporting features for many DMT instruments
simultaneously. It is useful if CCN data are being analyzed in conjunction with data from
other instruments.
PID: A proportional-integrative-derivative control system. PID systems have three
parameters that are used to determine a system’s corrective response to errors. (See
http://en.wikipedia.org/wiki/PID_controller for more information.) On the CCN, a PID
algorithm is used to modify the CCN’s proportional valve flow control loop. Users can
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modify the three PID parameters from the PID section of the DMT Service tab. See section
12.4.2.1 for details.
Proportional Valve (V): The voltage the computer sends to the proportional valve to
keep the CCN’s air flow constant.
Sample air: The air that the CCN samples for aerosol particles. The sample air is
confined to a small volume at the center of the CCN column. It is surrounded by sheath
air, with the sheath:sample volume ratio set at approximately 10:1.
Sample Flow (Vccm): The volumetric sample flow rate. Typically the ratio of sample
flow to sheath flow should be about 1:10, since the volume of sheath air should be about
ten times more than that of the sample air. If the observed ratio diverges significantly
from the set-point ratio for a prolonged period, the CCN computer generates an Alarm
Code.
Sample Temp (C): An output channel that indicates the temperature of the sample air.
When Sample Temp (C) exceeds its range for a sustained period, the CCN computer
generates an Alarm Code.
Sheath air: The air that surrounds the sample air in the CCN column. The sheath air acts
as a buffer to confine the sample.
Sheath Flow (Vccm): The volumetric flow rate of the sheath air. Typically the ratio of
sheath flow to sample flow should be about 10:1, since the volume of sheath air should
be about ten times more than that of the sample air. If the observed ratio diverges
significantly from the set-point ratio for a prolonged period, the CCN computer generates
an Alarm Code.
SS setting: An output data channel that stores the instrument’s current supersaturation.
A higher SS setting means that more particles will be detected.
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SS Table: A supersaturation table, or a table that determines the progression of
supersaturations settings the instrument will use in a sampling session. Users can select
among existing SS tables from the SS Tab, and they can create or modify available SS
tables using the CCN SS Config Editor.exe program.
Supersaturation:
The state at which air contains more water vapor than
thermodynamically allowed. The CCN counter uses supersaturation to grow aerosol
particles to detectible size.
T Inlet (C): The temperature of the CCN’s inlet manifold. When T Inlet (C) differs
substantially from its set point for a sustained period, the CCN computer generates an
Alarm Code.
T Nafion (C): The observed temperature at the Nafion humidifier. When Nafion Temp
(C) differs substantially from its set point for a sustained period, the CCN computer
generates an Alarm Code.
T OPC (C): The observed temperature of the CCN’s optical particle counter. When OPC
Temp (C) differs substantially from its set point for a sustained period, the CCN computer
generates an Alarm Code.
T1 Read (C): The temperature in the CCN’s top control zone.
T2 Read (C): The temperature in the CCN’s middle control zone.
T3 Read (C): The temperature in the CCN’s bottom control zone.
T1 Set (C): The set point temperature in the CCN’s top control zone.
T2 Set (C): The set point temperature in the CCN’s middle control zone.
T3 Set (C): The set point temperature in the CCN’s bottom control zone.
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TEC Relay: A control button on the Temps tab that switches the instrument’s 28 VDC
power buss on and off.
Temp Gradient: A CCN channel that stores the temperature gradient along the CCN’s
wetted walls, i.e. T3 Read (C) – T1 Read (C). The gradient is the controlling factor that
determines the instrument’s supersaturation.
Temp Stable?: A Boolean output channel indicating when T1, T2, or T3 Reads differs by
> 0.4 °C from its set point. A value of 1 indicates all three channels are close to their set
points. If Temp Stable? is 0 for a sustained period, the CCN computer generates an Alarm
Code. Note that Temp Stable? indicates temperature stability but does not necessarily
indicate data stability, which also depends on other factors.
Temperature Gradient / Thermal Gradient: The temperature gradient between T1 (the
top of the CCN column) and T3 (the bottom). See Delta T (C) for details.
Time: The time at which the computer writes the data from any given sampling instance
to the output file.
Total Flow (Vccm): The sum of the Sample Flow and the Sheath Flow. When the Total
Flow deviates from its set point for a prolonged period, the CCN computer generates an
Alarm Code.
Vccm: Volume cubic centimeters / minute. Vccm is a unit of flow.
Watch dog: An indicator on the Prog tab of the CCN control program. The indicator
alternates ON and OFF every second when the computer is cycling properly. The watch
dog light on the instrument should blink at the same time as this indicator. If the
indicator light is steady OFF or ON, reboot the computer.
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Zero-Count Test: A CCN test performed by installing a filter that is known to be working
well onto the CCN inlet, so that no aerosol particles can enter. The zero-count test
should result in a particle reading of 5/sec or less.
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Appendix B: Relationship between SS%, Particle
Concentration, and Percentage of CCN Counted
Tests at DMT have shown that the aerosol count rate in the CCN varies with SS% and
particle concentration. For concentrations at or below 6,000 particles/cc, all
supersaturations have a 90% or higher aerosol count rate. For instance, all the
supersaturation values plotted in Figure 51 have a 96% aerosol count rate at
concentrations of 5,000 particles/cc. At higher particle concentrations, however,
supersaturations below 0.2% show a decreased maximum count rate.
Note that observed and theoretical maximum concentrations differ considerably. On a
theoretical level, the instrument can count 60,000 particles/cc at a sample flow rate of
50 Vccm with a maximum coincidence of 10%. This 60,000 particles/cc figure is based
solely on the theoretical performance of the OPC, however; growth kinetics of particles
in the CCN column will reduce the actual concentration at which the instrument can
accurately detect particles.
Figure 51: Percentage of CCN Counted vs. Particle Concentration for Different SS%
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Appendix C: Assy, Cable 28V Power
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Appendix D: CCN Mounting Hole Locations
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Appendix E: CCN Aircraft Inlet (for Constant
Pressure Inlet)
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Appendix F: Exploded View of OPC
Figure 52: OPC Assembly, Exploded View
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Appendix
G:
Sheath
Flow
Filter
Testing
and
Replacement
Problem
Droplet Measurement Technologies (DMT) has recently become aware of a potential problem
with CCN sheath flow filter. The symptoms are that the CCN instrument counts too many
particles but will still zero count when a filter is installed on the inlet. These symptoms are
noticed when doing an intercomparison between the CCN counter and another instrument.
DMT researched changing to a different filter, but different pressure drops and physical sizes
made this unrealistic.
Recommendations
DMT is recommending all CCN Sheath flow filters currently in service either be replaced by
one tested by DMT (FL-0022, cost $20.00 each) or be removed and tested with a CN counter.
The background counts when tested on a CN counter should be very close to zero (<.5 per
ccm).
NOTE: if you use a different filter that has more of a pressure drop, you may not be able to
get a flow ratio of 10.
If you do not have access to a CN counter, the following procedure can be used to test the
sheath filter. A “bad” sheath filter will still zero count when a good filter is connected to the
inlet. This is due to the sheath air being pre-filtered by the inlet filter. You must isolate the
sheath flow filter.
1.
2.
3.
4.
5.
6.
Remove sheath line from manifold block.
Install ASSY-0122 plug (included in startup kit) into manifold as a plug.
Perform a leak check to ensure no leaks were induced.
Install DMT tested filter on inlet of CCN.
Run a scan that includes a 1% SS for at least 5 minutes
Counts should be less than 5 per update. If counts are higher, replace sheath filter
with DMT tested filter (new filters from DMT will have a “tested” label on them).
Caution: The filters may test well initially and then start to pass particles at a later date.
Thus we strongly recommend that the filters are replaced or the above test is performed
every 3 months. All filters in starter and service kits should also be tested; new filters from
DMT will have a “tested” label on them.
Please contact Rick Drgac at Droplet Measurement Technologies if you have any questions or
concerns,
or
if
you
need
to
order
replacement
filters.
Email
CCNInfo@dropletmeasurement.com; Phone: 303-440-5576 EX. 123
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Appendix H: International Shipping Certification
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Appendix I: Revisions to Manual
Rev. Date
Rev. No.
Summary
10/22/09
G-1
Revised Flow Calibration Procedure
Updated DMT’s address
10/26/09
G-1
Expanded typical Sample Flow (Vccm) and Sheath
Flow (Vccm) values; switched steps 3 & 4.
1/15/10
10/27/10
G-2
H
Updated pictures
Modified Sheath Flow Filter Testing and
Replacement Procedures
12/29/10
H-1
Modified theory of operation section
2.0
8/15/11
H-2
Updated instructions for checking unit functionality
3.3
9/1/11
H-3
9/27/11
10/4/11
I
I-1
Added descriptions of Inlet heater, Nafion heater,
and OPC heater indicator lights
Modified Flow Calibration procedure
Inserted photos of Metering Valve Access Port
4/18/12
I-2
Clarified procedures for fixing stuck reeds
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Section
8.2.2
Front
matter
8.2.2
Various
App. G
12.1.2
8.2
8.2
10.0
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